Metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode

Abstract

The present application provides a kind of rare earth nickel-based oxide electrode using platinum, gold, palladium as metal, by controlling the work function matching characteristics of metal electrode and rare earth nickel-based oxide, realize the technical method of low resistance ohmic contact to rare earth nickel-based oxide and control hydrogen-induced electronic phase change rate.For the electronic, hole mixed carrier electric transport mechanism of rare earth nickel-based oxide, the present application can realize low resistance ohmic contact under hole dominant transport by high work function metal or alloy contact, also can realize low resistance ohmic contact under electronic dominant transport by low work function metal or alloy contact.In addition, by regulating the work function matching relationship of metal and rare earth nickel-based oxide, control the hydrogen-induced electronic phase change rate and resistivity mutation degree of rare earth nickel-based oxide under hydrogen or mixed hydrogen atmosphere.The present application can be applied to the field of low resistance ohmic contact of mutation type thermistor, field effect transistor, logic device, reconfigurable electronic device, etc.

Description

Technical Field

[0001] This invention belongs to the field of metal semiconductors and electronic phase change materials, and relates to a metastable rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode. Background Technology

[0002] Rare earth nickel-based oxides (RENiO3, where RE represents rare earth elements) differ from traditional semiconductors in that they exhibit metal-insulator phase transition characteristics [Phase Transitions, 2008, 81, 729], meaning they undergo abrupt changes in electrical transport properties at specific temperatures. Compared to VO2, which exhibits similar metal-insulator phase transition characteristics, rare earth nickel-based oxides have the advantage of continuously adjustable phase transition temperatures over a wide temperature range of 100-600 K through various methods. This semiconductor material can achieve wide-range continuous control of its phase transition temperature by changing the rare earth element or Ni-site doping; for example, as the ionic radius of the A-site rare earth element increases, the phase transition temperature gradually decreases, and SmNi... 1-x Co x The increasing Co content in O3 leads to a gradual decrease in phase transition temperature. A continuous decrease in phase transition temperature can be achieved by applying external mechanical pressure; for example, the phase transition characteristics of PrNiO3 decrease to below 1.5K under 14.1 kbar pressure [Phys. Rev. B., 1993, 47, 12357]. The substrate template effect can also cause the phase transition temperature of thin film materials to deviate from the intrinsic phase transition temperature of bulk materials; for example, the phase transition temperature of NdNiO3 films grown on LaAlO3 substrates decreases by 50 degrees compared to the bulk material [J. Appl. Phys., 2013, 114, 243713]. Rare earth nickel-based oxides, due to their unique semiconductor properties, can be applied to optoelectronic devices, resistive devices, and magnetoresistive devices, such as photoelectric detection, infrared camouflage, Mott transistors, and magnetic transport. To achieve good phase transition characteristics of rare earth nickel-based oxides, the contact electrode should achieve ohmic contact with the rare earth nickel-based oxide; a small contact resistance does not affect the intrinsic electrical transport characteristics of the material.

[0003] Rare earth nickel-based oxides also exhibit hydrogen-induced phase transition properties, with proton insertion inducing changes in the orbital configuration of rare earth nickel-based oxides. to The strongly correlated state transition [Appl. Phys. Lett., 2015, 107, 031905]. It can achieve reversible insertion of dopants through chemical electronic doping, realizing reversible resistivity tuning up to eight orders of magnitude at room temperature [Nat. Commun., 2014, 5, 4860]. Hydrogen-induced phase change can be applied to low-temperature fuel cells; SmNiO3 can achieve this through spontaneous hydrogen or Li... + Na +The Mot transition caused by the incorporation of alkali metal ions can inhibit the electron conduction and act as a proton conductor, realizing the selective transport of electrons or ions in the external circuit

Nature, 2016, 534, 231

Nature, 2017, 553, 68

Nat. Commun., 2019, 10, 1651

Science, 2022, 375, 533

Adv. Mater., 2016, 28, 9117

[0004] In practical applications, the electrode metal should form an ohmic contact with the rare earth nickel-based oxide semiconductor, and a small conduction resistance is formed at the contact interface. Such electrode contact does not affect the resistance switching function characteristics of the rare earth nickel-based oxide and the device. To achieve ohmic contact, in general, when the metal work function is less than the N-type semiconductor work function, electrons transport to the semiconductor direction, and the electron concentration on the surface of the semiconductor is much larger than in the body, forming an interface high-conductivity zone, and forming an ohmic contact with the N-type semiconductor; when the metal work function is greater than the P-type semiconductor work function, holes transport to the semiconductor direction, and the hole concentration on the surface of the semiconductor is much larger than in the body, forming a surface high-conductivity zone, and forming an ohmic contact with the N-type semiconductor. Therefore, selecting a metal electrode material with an appropriate work function can obtain an ohmic contact.

[0005] Generally, platinum group Pt, Pd or complex multi-layer noble metals such as Ti / Au are selected as electrode contact materials for rare earth nickel-based oxides, among which Pt has the highest work function in a single metal, and noble metal Pt can form an ohmic contact with the P-type semiconductor rare earth nickel-based oxide dominated by hole carrier transport; at the same time, the Pt electrode can induce protons to spontaneously enter the rare earth nickel-based oxide lattice, which is an important medium for hydrogen-induced phase transition. However, practical applications are limited due to the high price of Pt electrode. Therefore, it is urgent to find a low-cost non-gold and non-platinum noble metal electrode material that can replace noble metal Pt, which can form a good ohmic contact with the rare earth nickel-based oxide semiconductor, and at the same time, this material can regulate the diffusion ability of protons along the surface of the rare earth nickel-based oxide to the interior of the material. SUMMARY

[0006] The present application aims to provide a metal semiconductor electrode contact electrode of a rare earth nickel-based oxide electronic phase change material other than noble metals such as platinum, gold, and palladium. For different compositions of the rare earth nickel-based oxide, the work function of the metal electrode is adjusted by selecting a metal element matched with the work function and forming a solid solution, an alloy compound, or an electrode array on the basis of the metal element, thereby regulating the migration characteristics of electrons, holes, and protons from the metal electrode to the inside of the rare earth nickel-based oxide, and achieving low resistance ohmic contact and improving the diffusion of protons into the inside of the rare earth nickel-based oxide. Based on the electronic and hole mixed carrier electric transport characteristics of the rare earth nickel-based oxide under the contact of different work function metals or alloy compounds, a non-noble metal and an alloy compound with a high work function (greater than 5.12 eV) are used as a metal semiconductor contact electrode dominated by hole carrier electric transport, and a non-noble metal and an alloy compound with a low work function (less than 4.72 eV) are used as a metal semiconductor contact electrode dominated by electron carrier electric transport. Based on the resistance jump caused by the hydrogen-induced electronic phase change of the rare earth nickel-based oxide, a high or low work function metal and its alloy compound are used to construct a proton barrier, regulate the thermodynamic and kinetic processes of the internal diffusion of protons, and regulate the hydrogen-induced electronic phase change characteristics of the rare earth nickel-based oxide. The metal electrode-rare earth nickel-based oxide electronic device prepared by using the present technology can be applied to the fields of low resistance ohmic contact of a jump type thermistor, a field effect transistor, a logic device, and a reconfigurable electronic device.

[0007] A metal semiconductor electrode contact electrode of a rare earth nickel-based oxide electronic phase change material is characterized in that a non-noble metal element or an alloy compound other than platinum, gold, and palladium is used as a contact electrode of the rare earth nickel-based oxide, the composition of the metal electrode is regulated to match the work function of the rare earth nickel-based oxide containing different rare earth elements, and the transport characteristics of electrons, holes, and protons at the interface between the metal electrode and the rare earth nickel-based oxide are regulated. Based on the hole and electron mixed carrier electric transport characteristics of the rare earth nickel-based oxide, on the one hand, the work function of the non-noble metal electrode is regulated to be much higher than that of the rare earth nickel-based oxide, and is selected to be greater than 5.12 eV, so as to realize the enrichment of holes on the surface of the rare earth nickel-based oxide and achieve low resistance ohmic contact. On the other hand, the work function of the non-noble metal electrode is regulated to be much lower than that of the rare earth nickel-based oxide, and is selected to be less than 4.72 eV, so as to realize the enrichment of electrons on the surface of the rare earth nickel-based oxide and achieve low resistance ohmic contact. On the other hand, in the hydrogen-induced electronic phase change of the rare earth nickel-based oxide, the work function of the surface metal electrode is regulated to control the Schottky barrier of protons passing through the interface between the metal and the oxide, so as to regulate the internal diffusion kinetics of protons along the interface and further control the hydrogen-induced electronic phase change rate and the resistance jump degree of the rare earth nickel-based oxide.

[0008] Further, the rare earth nickel-based oxide is a distorted perovskite oxide in a thermodynamic metastable state, which has a metal-insulator phase transition characteristic triggered by a characteristic temperature, and a hydrogen-induced electronic phase transition characteristic triggered by chemical and electrochemical hydrogen, which has a mixed electronic and hole transport mechanism; the structure is a RENiO3 perovskite structure: the RE site (A site) is a single rare earth element or a combination of multiple rare earth elements, including lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, samarium-neodymium, samarium-praseodymium, europium-neodymium, samarium-gadolinium, samarium-europium-gadolinium, etc.; the nickel element occupies the B site in the perovskite structure; by adjusting the rare earth element composition and occupancy ratio, the electronic structure, electrical transport characteristics, and work function of the rare earth nickel-based oxide can be controlled.

[0009] Further, the high work function metal electrode is a non-noble metal or alloy compound with a work function greater than 5.12 eV, which is much larger than the work function of the rare earth nickel-based oxide, and can drive the interface hole enrichment to form a low-resistance ohmic contact based on the hole transport mechanism. By selecting the type of metal electrode and adjusting the alloying components, the work function is matched with the functional characteristics of the rare earth nickel-based oxide. The selected electrode does not react with the rare earth nickel-based oxide at the use temperature, does not diffuse into the rare earth nickel-based oxide material, and is stable in air, and its liquid phase wets the surface of the rare earth nickel-based oxide, preferably Ni. In a preferred example, by growing a metal Ni electrode with a work function of 5.15 eV on different rare earth nickel-based oxides, the current-voltage curve is measured to have a linear characteristic, indicating that the Ni electrode forms an ohmic contact with the hole carrier electrical transport characteristic of the rare earth nickel-based oxide; in another preferred example, by forming an alloy compound by solid solution of Ni (work function 5.15 V) and Ir (work function 5.27 V), the work function of the nickel-iridium alloy is adjusted to 5.20 V, forming a low-resistance ohmic contact with the hole carrier electrical transport characteristic.

[0010] Further, the low work function metal electrode is a non-metallic single element or alloy compound with a work function less than 4.72 eV, which is much smaller than the work function of the rare earth nickel-based oxide, and can drive the interface electron enrichment to form a low resistance ohmic contact based on the electron transport mechanism. By selecting the type of metal electrode and adjusting the alloying components, the work function is matched with the functional characteristics of the rare earth nickel-based oxide. The selected electrode does not react with the rare earth nickel-based oxide at the use temperature, does not diffuse into the rare earth nickel-based oxide material, and is stable in air. The liquid phase of the electrode wets the surface of the rare earth nickel-based oxide, and the electrode is preferably Cu, Fe, In. In a preferred example, by growing a metal Cu with a work function of 4.65 eV on different rare earth nickel-based oxides as an electrode, the current-voltage curve is measured to have a linear characteristic, indicating that the Cu electrode forms an ohmic contact with the electron carrier electric transport characteristics of the rare earth nickel-based oxide; in another preferred example, by forming an alloy compound by solid solution of Cu (work function 4.65 V) and W (work function 4.55 V), the work function of the tungsten-copper alloy is adjusted to 4.61 V, forming a low resistance ohmic contact with the electron carrier electric transport characteristics.

[0011] Further, by adjusting the work function of the contact metal, the Schottky barrier strength of protons driven through the metal oxide interface and into the rare earth nickel-based oxide under hydrogen, mixed hydrogen atmosphere can be adjusted. Metals with high work functions can induce the inward diffusion of protons into the rare earth nickel-based oxide, and metals with low work functions can shield the inward diffusion of protons, thereby adjusting the rate of hydrogen-induced electronic phase transition of the rare earth nickel-based oxide and the degree of resistance mutation caused by it. In a preferred example, using a point-like Cu as a surface electrode of SmNiO3 can inhibit the hydrogen-induced electronic phase transition, thereby maintaining the resistivity of SmNiO3 in hydrogen; in another preferred example, using a point-like Cu / Ru alloy with the same size as a surface electrode of SmNiO3 can promote the hydrogen-induced electronic phase transition of SmNiO3 under the same hydrogen conditions, thereby increasing the resistivity of SmNiO3 in hydrogen by 1000 times; in another preferred example, using a point-like copper-ruthenium alloy with the same size as a surface electrode of SmNiO3 can control the hydrogen-induced electronic phase transition rate between the above two under the same hydrogen conditions, thereby increasing the resistivity of SmNiO3 in hydrogen by 300 times.

[0012] The rare earth nickel-based oxide metal element or alloy material used in the present application has a significantly reduced cost compared to platinum, gold, and palladium reported in the past. Among them, the metal element used is a non-noble metal, and the amount of noble metal in the alloy is also greatly reduced compared to the past reports. For different compositions of rare earth nickel-based oxides, the above metal or alloy electrode can directly cover the surface of the rare earth nickel-based oxide material as an electrode, can be solid-solution formed with other metals to form an alloy, and can also be arranged alternately in an array form on the surface of the rare earth nickel-based oxide; the growth method of the metal electrode includes but is not limited to magnetron sputtering growth, electron beam evaporation growth, chemical vapor deposition growth, spin-on paste growth, etc., and the thickness of the contact electrode ranges from 1 nm to 50 nm. In a preferred example, by growing metal Ni, Cu alternating array electrodes on the rare earth nickel-based oxide, the metal-rare earth nickel-based oxide contact ohmic resistance is further reduced; in another preferred example, by magnetron sputtering to grow polycrystalline metal Cu as an electrode on different rare earth nickel-based oxides, the metal Cu electrode is in close contact with the rare earth nickel-based oxide, reducing the additional resistance introduced by defects, and further reducing the ohmic contact resistance.

[0013] Through extensive and in-depth research, the present application has invented a metal semiconductor non-gold, non-platinum, and non-palladium noble metal electrode contact technology for rare earth nickel-based oxide electronic phase change materials. The main idea of the present application is to adjust the electron, hole, and proton transport characteristics of the rare earth nickel-based oxide through metal work function matching and alloyed work function design, to realize the functions of low resistance ohmic contact and hydrogen-induced phase change regulation; some high work function metals and alloy compounds can form ohmic contact based on the hole transport mechanism of the rare earth nickel-based oxide, while promoting the hydrogen-induced phase change of the material in a hydrogen atmosphere; and some low work function metals can form ohmic contact based on the electron transport mechanism of the rare earth nickel-based oxide, while inhibiting the hydrogen-induced phase change of the material in a hydrogen atmosphere, and improving the stability of the device. Compared with previous research, the present application is based on the electron, hole, and proton transport behavior of the rare earth nickel-based oxide, and one or more metals and alloy compounds are designed to form ohmic contact or Schottky contact with the rare earth nickel-based oxide, to realize multiple regulation of the resistance change behavior of the rare earth nickel-based oxide and regulation of the hydrogen atmosphere stability of the rare earth nickel-based oxide electronic device. At the same time, the present application uses non-gold, non-platinum, and non-palladium noble metal electrode materials to greatly reduce the cost of the device. The metal electrode-rare earth nickel-based oxide electronic device prepared by using the present technology can be applied to the fields of field effect transistors, logic devices, abrupt thermistors, reconfigurable electronic devices, etc. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The figure shows the schematic diagram of high and low work functions forming ohmic contact with the rare earth nickel-based oxide. As can be seen, when the metal work function is greater than 5.12 eV, holes are enriched at the interface, and when the metal work function is less than 4.72 eV, electrons are enriched at the interface, which is conducive to the formation of ohmic contact.

[0015] Figure 2 The current-voltage curve of the Ni electrode of NdNiO3 is shown in the figure. It can be seen that the current-voltage curve is a straight line, indicating that the Ni electrode forms ohmic contact with NdNiO3.

[0016] Figure 3 The current-voltage curve of the Cu electrode of NdNiO3 is shown in the figure. It can be seen that the current-voltage curve is a straight line, indicating that the Cu electrode forms ohmic contact with NdNiO3.

[0017] Figure 4 The resistance-temperature curve of the Ni electrode of NdNiO3 and NdNiO3 is shown in the figure. It can be seen that the resistance-temperature curve of the Ni electrode two-terminal method is similar to that of the intrinsic four-terminal method of the NdNiO3 film, indicating that the Ni electrode forms ohmic contact with NdNiO3.

[0018] Figure 5 The resistance-temperature curve of the Cu electrode of NdNiO3 and NdNiO3 is shown in the figure. It can be seen that the resistance-temperature curve of the Cu electrode two-terminal method is similar to that of the intrinsic four-terminal method of the NdNiO3 film, indicating that the Cu electrode forms ohmic contact with NdNiO3.

[0019] Figure 6 The current-voltage curve of the Cu electrode of NdNiO3 at 50K-300K is shown in the figure. It can be seen that the current-voltage curve at different temperatures is a straight line, indicating that the Cu electrode forms ohmic contact with NdNiO3.

[0020] Figure 7 The resistance-time curve of the Ru / Cu alloy electrode, Ag electrode, and Cu electrode of NdNiO3 in a 4% hydrogen atmosphere at 100°C for 100 minutes is shown in the figure. It can be seen that the Ru / Cu alloy electrode can induce the inward diffusion of protons into the rare earth nickel-based oxide to induce hydrogen-induced resistance switching, and the Ag electrode and Cu electrode have a shielding effect on the inward diffusion of protons. DETAILED DESCRIPTION

[0021] Unless otherwise specified, the various raw materials of the present application can be obtained commercially; or prepared according to conventional methods in the art. Unless otherwise defined or specified, all professional and scientific terms used herein have the same meaning as understood by those skilled in the art. In addition, any method and material similar or equivalent to those described can be applied to the method of the present application.

[0022] Other aspects of the present application will be apparent to those skilled in the art from consideration of the disclosure herein.

[0023] The application will be further described in connection with the following specific examples. It should be understood that these examples are only for the purpose of illustration and are not intended to limit the scope of the application. The experimental methods in the following examples, if not otherwise specified, are usually carried out under conventional conditions or under the conditions recommended by the manufacturer.

[0024] Test methods: We used JISL 4200 semiconductor analyzer, VersLab, step meter and other means to characterize the prepared rare earth nickel-based oxide metal electrode contact pair. The characterization method is according to the general standard in the art.

[0025] Example 1:

[0026] A metal Ni strip electrode was grown on the NdNiO3 thin film using magnetron sputtering under an argon atmosphere of 0.4 Pa at room temperature for 15 minutes to obtain a Ni electrode with a thickness of about 50 nm. The room temperature current-voltage curve of the Ni electrode and the NdNiO3 thin film is shown in FIG. 1, which is a straight line, indicating that the Ni electrode forms an ohmic contact with the NdNiO3 thin film with hole carrier transport characteristics, as shown in FIG. 2. The resistance-temperature curve of the Ni electrode was measured, and it was found that the resistance-temperature curve obtained by the two-terminal method of the Ni electrode was similar to that obtained by the four-terminal method of the intrinsic NdNiO3 thin film, as shown in FIG. 3, proving the ohmic contact behavior of the Ni and NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electronic phase transition of the NdNiO3 thin film, indicating that the Ni electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. Figure 2 Figure 1 Figure 4

[0027] Example 2:

[0028] A metal Cu strip electrode was grown on the NdNiO3 thin film using magnetron sputtering under an argon atmosphere of 0.4 Pa at room temperature for 15 minutes to obtain a Cu electrode with a thickness of about 50 nm. The room temperature current-voltage curve of the Cu electrode and the NdNiO3 thin film is shown in FIG. 4, which is a straight line, indicating that the Cu electrode forms an ohmic contact with the NdNiO3 thin film with electron carrier transport characteristics, as shown in FIG. 5. The resistance-temperature curve of the Cu electrode was measured, and it was found that the resistance-temperature curve obtained by the two-terminal method of the Cu electrode was similar to that obtained by the four-terminal method of the intrinsic NdNiO3 thin film, as shown in FIG. 6, proving the ohmic contact behavior of the Cu and NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electronic phase transition of the NdNiO3 thin film, indicating that the Cu electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. Figure 3 Figure 1 Figure 5

[0029] Example 3:

[0030] ​​​​​​A metallic In strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under 2 Pa argon atmosphere for 15 min to obtain an In electrode with a thickness of about 50 nm. The current-voltage curve of the In electrode was measured to be a straight line, indicating that the In electrode forms an ohmic contact with the NdNiO3 thin film with electron carrier transport characteristics, as shown in Fig. 1. The resistance-temperature curve of the In electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 thin film measured by the four-probe method, proving the ohmic contact behavior of the In electrode with the NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electron phase transition of the NdNiO3 thin film, indicating that the In electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. Figure 1

[0031] Example 4:

[0032] A NiIr alloy strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under 0.8 Pa argon atmosphere for 10 min to obtain a NiIr alloy electrode with a thickness of about 50 nm. The work function of the NiIr alloy strip electrode was regulated by alloying. The current-voltage curve of the NiIr alloy electrode was measured to be a straight line, indicating that the NiIr alloy forms an ohmic contact with the NdNiO3 thin film with electron carrier transport characteristics, as shown in Fig. 2. The resistance-temperature curve of the NiIr alloy electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 thin film measured by the four-probe method, proving the ohmic contact behavior of the NiIr alloy with the NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electron phase transition of the NdNiO3 thin film, indicating that the NiIr alloy electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. Figure 1

[0033] Example 5:

[0034] A WCu alloy strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under 0.4 Pa argon atmosphere for 10 min to obtain a WCu alloy electrode with a thickness of about 50 nm. The current-voltage curve of the WCu alloy electrode was measured to be a straight line, indicating that the WCu alloy forms an ohmic contact with the NdNiO3 thin film with electron carrier transport characteristics, as shown in Fig. 3. The resistance-temperature curve of the WCu alloy electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 thin film measured by the four-probe method, proving the ohmic contact behavior of the WCu alloy with the NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electron phase transition of the NdNiO3 thin film, indicating that the WCu alloy electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. Figure 1

[0035] Example 6:

[0036] A W strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under 0.4 Pa argon atmosphere for 10 min to obtain a W electrode with a thickness of about 50 nm. The current-voltage curve of the W electrode was measured to be a straight line, indicating that the W electrode forms an ohmic contact with the NdNiO3 thin film with electron carrier transport characteristics, as shown in Fig. 4. The resistance-temperature curve of the W electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 thin film measured by the four-probe method, proving the ohmic contact behavior of the W electrode with the NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electron phase transition of the NdNiO3 thin film, indicating that the W electrode can replace the noble metal Pt as the electrode of the NdNiO3 thin film. 0.25 Sm 0.75 ​​​A Cu electrode with a thickness of approximately 50 nm was obtained by growing a Cu strip on a NiO3 thin film for 15 minutes. The room temperature current-voltage curve of the electrode was linear, demonstrating the interaction between Cu and Nd+ electron carrier transport properties. 0.25 Sm 0.75 NiO3 thin films form ohmic contacts, such as Figure 1 As shown, measuring its resistance-temperature curve reveals that the Cu electrode's resistance-temperature curve is similar to that of Nd. 0.25 Sm 0.75 The resistance-temperature curves obtained by the intrinsic four-terminal method for NiO3 thin films are similar, proving that Cu and Nd... 0.25 Sm 0.75 The ohmic contact behavior of NiO3 thin film materials shows that contact resistance does not affect Nd. 0.25 Sm 0.75 The intrinsic electronic phase transition of the NiO3 thin film indicates that Cu electrodes can replace noble metal Pt as Nd. 0.25 Sm 0.75 NiO3 thin film electrode.

[0037] Example 7:

[0038] A Cu strip electrode with a thickness of approximately 50 nm was grown on a SmNiO3 thin film by magnetron sputtering for 15 minutes at room temperature under an argon atmosphere of 0.4 Pa. The linear current-voltage curve at room temperature indicates that Cu forms an ohmic contact with the SmNiO3 thin film, which exhibits excellent electron carrier transport properties. Figure 1 As shown, the resistance-temperature curves obtained by measuring the Cu electrode at both ends and the intrinsic four-end method of the SmNiO3 thin film are similar, which proves the ohmic contact behavior between Cu and SmNiO3 thin film materials. The contact resistance does not affect the intrinsic electronic phase transition of the SmNiO3 thin film, indicating that the Cu electrode can replace the noble metal Pt as the electrode of the SmNiO3 thin film.

[0039] Example 8:

[0040] A Ni electrode with a thickness of approximately 50 nm was grown on a GdNiO3 film by magnetron sputtering at room temperature (7 Pa) under an argon atmosphere for 12 minutes. The room temperature current-voltage curve was linear, indicating that Ni forms an ohmic contact with the GdNiO3 film, which exhibits excellent hole carrier transport properties. Figure 1 As shown, the resistance-temperature curves obtained by measuring the Ni electrode two-end method are similar to those obtained by the intrinsic four-end method of GdNiO3 thin film, which proves the ohmic contact behavior between Ni and GdNiO3 thin film materials. The contact resistance does not affect the intrinsic electronic phase transition of GdNiO3 thin film, indicating that Ni electrode can replace noble metal Pt as GdNiO3 thin film electrode.

[0041] Example 9:

[0042] A Cu electrode with a thickness of about 50 nm was grown on the NdNiO3 film by electron beam evaporation under an argon atmosphere of 0.4 Pa at room temperature for 10 minutes. The current-voltage curve of the Cu electrode at room temperature was measured to be a straight line, indicating that the Cu electrode formed an ohmic contact with the NdNiO3 film with electron carrier transport characteristics, as shown in Fig. 1. The resistance-temperature curve of the Cu electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 film measured by the four-probe method, proving the ohmic contact behavior of the Cu electrode with the NdNiO3 film material, and the contact resistance did not affect the intrinsic electron phase transition of the NdNiO3 film, indicating that the Cu electrode can replace the noble metal Pt as the electrode of the NdNiO3 film. Figure 1

[0043] Example 10

[0044] A Cu electrode with a thickness of about 200 nm was grown on the NdNiO3 film by magnetron sputtering under an argon atmosphere of 0.4 Pa at room temperature for 60 minutes. The current-voltage curve of the Cu electrode at room temperature was measured to be a straight line, indicating that the Cu electrode formed an ohmic contact with the NdNiO3 film with electron carrier transport characteristics, as shown in Fig. 2. The resistance-temperature curve of the Cu electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 film measured by the four-probe method, proving the ohmic contact behavior of the Cu electrode with the NdNiO3 film material, and the contact resistance did not affect the intrinsic electron phase transition of the NdNiO3 film, indicating that the Cu electrode can replace the noble metal Pt as the electrode of the NdNiO3 film. Figure 1

[0045] Example 11

[0046] A Cu electrode with a thickness of about 50 nm was grown on the NdNiO3 film by magnetron sputtering under an argon atmosphere of 0.4 Pa at room temperature for 15 minutes. The current-voltage curve of the Cu electrode at room temperature was measured to be a straight line, indicating that the Cu electrode formed an ohmic contact with the NdNiO3 film with electron carrier transport characteristics, as shown in Fig. 3. The resistance-temperature curve of the Cu electrode was measured to be similar to the resistance-temperature curve of the NdNiO3 film measured by the four-probe method, proving the ohmic contact behavior of the Cu electrode with the NdNiO3 film material, and the contact resistance did not affect the intrinsic electron phase transition of the NdNiO3 film, indicating that the Cu electrode can replace the noble metal Pt as the electrode of the NdNiO3 film. Figure 1

[0047] Example 12

[0048] ​​​A Cu strip electrode of about 50 nm thick was grown on the NdNiO3 thin film by magnetron sputtering at room temperature under an argon atmosphere of 0.4 Pa for 15 minutes, and a Ni strip electrode of about 50 nm thick was grown on the NdNiO3 thin film by magnetron sputtering at room temperature under an argon atmosphere of 0.4 Pa for 15 minutes to form an electrode array of Cu strip and Ni strip, and a straight line of the room temperature current-voltage curve thereof indicates that the electrode array of Cu strip and Ni strip forms an ohmic contact with the NdNiO3 thin film of mixed carrier transport characteristics of electrons and holes, as shown in FIG. 1. Figure 1 As shown in FIG. 2, the resistance-temperature curve of the electrode array of Cu strip and Ni strip was measured, and it was found that the resistance-temperature curve obtained by the two-terminal method of the electrode array of Cu strip and Ni strip is similar to the resistance-temperature curve obtained by the four-terminal method of the NdNiO3 thin film, proving the ohmic contact behavior of the electrode array of Cu strip and Ni strip with the NdNiO3 thin film material, and the contact resistance does not affect the intrinsic electronic phase transition of the NdNiO3 thin film, indicating that the electrode array of Cu strip and Ni strip can replace the noble metal Pt as the electrode of the NdNiO3 thin film.

[0049] Example 13

[0050] A Ni-Cu double-layer electrode structure was formed by growing a Ni strip electrode of about 10 nm thick on the NdNiO3 thin film by magnetron sputtering at room temperature under an argon atmosphere of 0.4 Pa for 3 minutes, and growing a Cu electrode of about 40 nm thick on the Ni electrode by magnetron sputtering at room temperature under an argon atmosphere of 0.4 Pa for 12 minutes, and a straight line of the room temperature current-voltage curve thereof indicates that the Ni-Cu double-layer electrode forms an ohmic contact with the NdNiO3 thin film of hole carrier transport characteristics, as shown in FIG. 4. Figure 1 As shown in FIG. 5, the resistance-temperature curve of the Ni-Cu double-layer electrode was measured, and it was found that the resistance-temperature curve obtained by the two-terminal method of the Ni-Cu double-layer electrode is similar to the resistance-temperature curve obtained by the four-terminal method of the NdNiO3 thin film, proving the ohmic contact behavior of the Ni-Cu double-layer electrode with the NdNiO3 thin film material, and further reducing the contact resistance.

[0051] Example 14

[0052] A Co point electrode of about 50 nm thick was grown on the NdNiO3 thin film by magnetron sputtering at room temperature under an argon atmosphere of 1.6 Pa for 15 minutes, and a straight line of the room temperature current-voltage curve thereof indicates that the Co forms a Schottky contact with the NdNiO3 thin film, and the current-voltage curve thereof measured after standing in a 5% hydrogen atmosphere at 100°C for 30 minutes shows that the thin film has a huge hydrogen-induced resistance jump, indicating that the Co forms a Schottky contact with the NdNiO3 thin film, and regulates the diffusion ability of protons along the surface of the rare earth nickel-based oxide to the interior of the material, achieving the purpose of regulating the hydrogen-induced electronic phase transition characteristics of the rare earth nickel-based oxide.

[0053] Example 15

[0054] A metal Ni strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under an argon atmosphere at 3 Pa for 15 minutes to obtain a Ni electrode with a thickness of about 50 nm. The current-voltage curve of the Ni electrode was measured to be a straight line, indicating that the Ni electrode formed an ohmic contact with the hole carrier transport characteristic NdNiO3 thin film, as shown in FIG. 1. After being placed in a 5% hydrogen atmosphere at 100°C for 30 minutes, the current-voltage curve of the Ni electrode was measured to be a straight line, and a hydrogen-induced resistance abrupt change occurred, indicating that the Ni electrode formed an ohmic contact with the NdNiO3 thin film and promoted the diffusion of protons along the surface of the rare earth nickel-based oxide to the interior of the material, thereby achieving the purpose of regulating the hydrogen-induced electronic phase change characteristic of the rare earth nickel-based oxide. Figure 1

[0055] Example 16

[0056] A metal Cu strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under an argon atmosphere at 0.4 Pa for 15 minutes to obtain a Cu electrode with a thickness of about 50 nm. The current-voltage curve of the Cu electrode was measured to be a straight line, indicating that the Cu electrode formed an ohmic contact with the electron carrier transport characteristic NdNiO3 thin film, as shown in FIG. 2. After being placed in a 5% hydrogen atmosphere at 100°C for 30 minutes, the current-voltage curve of the Cu electrode was measured to be a straight line, and no hydrogen-induced resistance abrupt change occurred, indicating that the Cu electrode formed an ohmic contact with the NdNiO3 thin film and inhibited the diffusion ability of protons along the surface of the rare earth nickel-based oxide to the interior of the material, thereby making the rare earth nickel-based oxide as a sensitive material electronic device have higher functional stability. ​

[0057] Example 17

[0058] A metal Cu strip electrode was grown on the NdNiO3 thin film using magnetron sputtering at room temperature under an argon atmosphere at 0.4 Pa for 15 minutes to obtain a Cu electrode with a thickness of about 50 nm. The current-voltage curve of the Cu electrode was measured to be a straight line, indicating that the Cu electrode formed an ohmic contact with the electron carrier transport characteristic NdNiO3 thin film, as shown in FIG. 2. After being placed in a 5% hydrogen atmosphere at 100°C for 30 minutes, the current-voltage curve of the Cu electrode was measured to be a straight line, and no hydrogen-induced resistance abrupt change occurred, indicating that the Cu electrode formed an ohmic contact with the NdNiO3 thin film and inhibited the diffusion ability of protons along the surface of the rare earth nickel-based oxide to the interior of the material, thereby making the rare earth nickel-based oxide as a sensitive material electronic device have higher functional stability.

[0059] ​​The above merely describes the preferred embodiments of the present application, and is not intended to limit the scope of the technical content of the present application. The technical content of the present application is broadly defined in the scope of the claims of the application. Any technical entity or method completed by others, if it is exactly the same as or an equivalent change of the scope defined by the claims of the application, will be considered to be covered in the scope of the claims.

Claims

1. A metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-precious metal contact electrode, characterized in that, The non-noble metal element or alloy compound other than platinum, gold and palladium is used as the rare earth nickel-based oxide contact electrode, the function matching between the metal electrode component and the rare earth nickel-based oxide containing different rare earth elements is realized by regulating the metal electrode component, and the transport characteristics of electrons, holes and protons at the interface between the metal electrode and the rare earth nickel-based oxide are regulated; Based on the hole and electron mixed carrier electric transport characteristics of the rare earth nickel-based oxide, on one hand, the non-noble metal electrode function is regulated to be much higher than the rare earth nickel-based oxide, and is selected to be greater than 5.12 eV, so that the holes on the surface of the rare earth nickel-based oxide are enriched, and low-resistance ohmic contact is realized; on the other hand, the non-noble metal electrode function is regulated to be much lower than the rare earth nickel-based oxide, and is selected to be less than 4.72 eV, so that the electrons on the surface of the rare earth nickel-based oxide are enriched, and low-resistance ohmic contact is realized; on the other hand, in the hydrogen-induced electronic phase transition of the rare earth nickel-based oxide, the surface metal electrode function is regulated to control the Schottky barrier of protons through the metal-oxide interface, so that the regulation of the internal diffusion dynamics of protons along the interface is realized, and the hydrogen-induced electronic phase transition rate and the resistance mutation degree of the rare earth nickel-based oxide are further controlled; By adjusting the work function of the contact metal, the Schottky barrier strength of protons driven by hydrogen or mixed hydrogen atmosphere through the metal-oxide interface and into the rare earth nickel-based oxide can be regulated, the metal with high work function can induce the internal diffusion of protons into the rare earth nickel-based oxide, and the metal with low work function has a shielding effect on the internal diffusion of protons, so that the hydrogen-induced electronic phase transition rate and the resistance mutation degree of the rare earth nickel-based oxide are regulated; The low work function metal electrode is a non-metallic element or alloy compound with a work function less than 4.72 eV, which is much smaller than the work function of the rare earth nickel-based oxide, can drive the interface to be electron-rich, and form low-resistance ohmic contact based on the electron transport mechanism; by regulating the type and alloy component of the metal electrode, the work function is matched with the functional characteristics of the rare earth nickel-based oxide; the selected low work function metal electrode does not react with the rare earth nickel-based oxide at the use temperature, does not diffuse into the rare earth nickel-based oxide material, and is stable in air, the liquid phase of the low work function metal electrode wets the surface of the rare earth nickel-based oxide, and the low work function metal electrode is selected as Cu, Fe and In.

2. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-precious metal contact electrode of claim 1, wherein, wherein, The rare earth nickel-based oxide is a distorted perovskite oxide in a thermodynamic metastable state, which has metal-insulator phase transition characteristics under a characteristic temperature trigger, and hydrogen-induced electronic phase transition characteristics under chemical and electrochemical hydrogen triggers, and has a mixed electronic and hole transport mechanism; the structure is a RENiO3 perovskite structure: the RE site is an A site, which is a single rare earth element or a combination of multiple rare earth elements, including lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, samarium-neodymium: Sm x Nd 1-x , 0 < x < 1, samarium-praseodymium: Sm x Pr 1-x , 0 < x < 1, europium-neodymium: Eu x Nd 1-x , 0 < x < 1, samarium-gadolinium: Sm x Gd 1-x , 0 < x < 1, samarium-europium-gadolinium: Sm x Eu y Gd 1-x-y , 0 < x, y, x + y < 1; the nickel element occupies the B site in the perovskite structure; by adjusting the rare earth element composition and the occupation ratio, the electronic structure and the electrical transport characteristics and the work function of the rare earth nickel-based oxide can be adjusted.

3. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode as claimed in claim 1, wherein, The high work function metal electrode is a non-noble metal or alloy compound with a work function greater than 5.12 eV, which is much greater than the work function of the rare earth nickel-based oxide, can drive the interface to be hole-rich, and form low-resistance ohmic contact based on the hole transport mechanism; by regulating the type and alloy component of the metal electrode, the work function is matched with the functional characteristics of the rare earth nickel-based oxide; the selected high work function metal electrode does not react with the rare earth nickel-based oxide at the use temperature, does not diffuse into the rare earth nickel-based oxide material, and is stable in air, the liquid phase of the high work function metal electrode wets the surface of the rare earth nickel-based oxide, and the high work function metal electrode is selected as Ni.

4. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode of claim 3 wherein, By growing the metal Ni with work function of 5.15eV as electrode on different rare earth nickel-based oxides, the current-voltage curve has linear characteristics, indicating that the Ni electrode and the hole carrier electric transport characteristic of the rare earth nickel-based oxides form ohmic contact.

5. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode of claim 3 wherein, By growing the metal Ni with work function of 5.15eV as electrode on different rare earth nickel-based oxides, the current-voltage curve has linear characteristics, indicating that the Ni electrode and the hole carrier electric transport characteristic of the rare earth nickel-based oxides form ohmic contact.

6. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode of claim 1 wherein, By growing the metal Cu with work function of 4.65eV as electrode on different rare earth nickel-based oxides, the current-voltage curve has linear characteristics, indicating that the Cu electrode and the electron carrier electric transport characteristic of the rare earth nickel-based oxides form ohmic contact.

7. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode of claim 1 wherein, By growing the metal Cu with work function of 4.65eV as electrode on different rare earth nickel-based oxides, the current-voltage curve has linear characteristics, indicating that the Cu electrode and the electron carrier electric transport characteristic of the rare earth nickel-based oxides form ohmic contact.

8. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-noble metal contact electrode of claim 1 wherein, Using the same size of point Cu / Ru alloy as the surface electrode of SmNiO3 can promote the hydrogen-induced electronic phase transition of SmNiO3 under the same hydrogen conditions, so that the resistivity of SmNiO3 increases by 1000 times in hydrogen.

9. The metastable phase rare earth nickel-based oxide electronic phase change semiconductor non-precious metal contact electrode of claim 1 wherein, For different compositions of rare earth nickel-based oxides, the above metal or alloy electrode can be directly used as an electrode to cover the surface of the rare earth nickel-based oxide material, can be solid-solution formed with other metals to form an alloy, and can be arranged in an array form on the surface of the rare earth nickel-based oxide; the growth method of the metal electrode includes but is not limited to magnetron sputtering growth, electron beam evaporation growth, chemical vapor deposition growth, and spin-on paste growth method, and the thickness of the contact electrode ranges from 1nm to 50nm.

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