Photoelectric memristor based on plasmonic resonance enhanced absorption and preparation method thereof

Abstract

This invention discloses a photoelectric memristor based on plasmon resonance enhanced absorption and its fabrication method, solving the technical problems of narrow spectral response and limited ability of light-absorbed excited charge carriers to control the conductive filament in existing conductive filament memristors. The photoelectric memristor based on plasmon resonance enhanced absorption comprises, from bottom to top, a metal electrode, a substrate, a defect-state semiconductor thin film, a nano-metal particle film, and a transparent electrode stacked sequentially; an ohmic contact is formed between the metal electrode and the substrate; the defect-state semiconductor thin film is an oxide, a sulfide, or a selenide, with a defect concentration of 10. 16 -10 18 / cm 3 The average particle size of the nano-metal particles in the nano-metal particle film is adapted to the wavelength of the external incident light; the transparent electrode is tightly bonded to the nano-metal particle film and directly contacts the defect-state semiconductor film at the gap between each nano-metal particle.

Description

Technical Field

[0001] This invention relates to photoelectric memristors and their fabrication methods, specifically to a photoelectric memristor based on plasma resonance enhanced absorption and its fabrication method. Background Technology

[0002] A typical two-terminal memristor has a metal-dielectric-metal structure. The physical state of the dielectric layer can be reconstructed by an external excitation field, and the modulated physical state depends on the history of the applied external excitation. Memristors with different physical states exhibit different resistance states, and the memristor displays resistance change behavior during the application of external excitation, which gives the memristor the characteristics of a basic memory.

[0003] The physical mechanisms of memristors can be mainly divided into three categories: First, the conductive filament type, where an electric field can drive the migration of cations / anions in the dielectric layer, thereby controlling the formation and breakage of the conductive filaments connecting the two electrodes. The resistance state of the memristor depends on the size and stability of the conductive filaments. Second, the non-conductive filament type, where the resistance state of the memristor is determined by the carrier capture / decapture effect in the dielectric layer, or by the Schottky barrier and tunneling barrier at the interface modulated by ion migration. Third, the phase change type, which differs from the local ion migration physical mechanism in common memristors, the thermal effect generated by external electrical stimulation causes the phase change layer of the phase change memristor to switch between an amorphous phase (high resistance state) and a crystalline phase (low resistance state).

[0004] Traditional memristors typically use a single electrical signal as both input and control signal. However, optical signals, due to their advantages such as high transmission speed and low power consumption, can also be used as input signals or auxiliary control methods for memristors. Memristors involving optical signals are called opto-memristors, and they exhibit excellent performance in simulating biological synaptic properties and in synaptic biomimetic applications.

[0005] Most common conductive filament-based opto-memristors are based on the principles of oxygen / sulfur vacancy conductive filaments and metal ion filaments. In terms of material selection, oxygen vacancies are mostly found in wide-bandgap oxide semiconductors, while sulfur vacancies and metal ions are mostly found in sulfide semiconductors. This results in narrow spectral responses, with most materials only responding to ultraviolet-visible light and weak near-infrared / short-wave infrared responses. Currently, it is difficult to cover the optical communication and imaging bands. Furthermore, the relatively slow ion migration rate severely limits the switching speed of opto-memristors. In addition, the ability of carriers excited by light absorption in semiconductors to control the conductive filaments is limited, resulting in small photocurrent variations and low signal-to-noise ratios for optical writing / reading. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of existing conductive filament memristors having a narrow spectral response, making it difficult to cover optical communication and imaging bands, and having limited ability to control the conductive filament by carriers excited by light absorption. The invention provides a photoelectric memristor based on plasmonic resonance enhanced absorption and its fabrication method.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0008] A photoelectric memristor based on plasma resonance enhanced absorption is characterized by comprising a metal electrode, a substrate, a defect-state semiconductor thin film, a nano-metal particle film, and a transparent electrode stacked sequentially from bottom to top.

[0009] An ohmic contact is formed between the metal electrode and the substrate;

[0010] The defect-state semiconductor thin film is an oxide, a sulfide, or a selenide, and its defect concentration is 10. 16 -10 18 / cm 3 The defect-state semiconductor thin film is used to migrate and form conductive channels after an external excitation electric field is applied, thereby achieving the switching of the resistance state of the defect-state semiconductor thin film; wherein, the resistance state includes a high-resistance state and a low-resistance state.

[0011] The nano-metal particle film is used to inject electrons generated by plasma resonance into the defect-state semiconductor film after external light irradiation, thereby disrupting the conductive channels formed in the defect-state semiconductor film and switching the resistive state of the defect-state semiconductor film; the average particle size of the nano-metal particles in the nano-metal particle film is adapted to the wavelength of the external incident light.

[0012] The transparent electrode is tightly bonded to the nano-metal particle film and directly contacts the defect-state semiconductor film at the gaps between the nano-metal particles to form a conductive path.

[0013] Furthermore, the metal electrode is made of one of gold, silver, copper, or aluminum;

[0014] The thickness of the metal electrode is 200nm-500nm.

[0015] Furthermore, the substrate material is one of Si, NSTO, and InP;

[0016] The defect-state semiconductor thin film is made of one of the following materials: ZnO, IGZO, SnO2, TiO2, WO3, MoS2, CdS, and CdSe.

[0017] Furthermore, the nano-metal particle film is made of one of gold, silver, platinum, or aluminum.

[0018] Furthermore, in the nano-metal particle film, 80%-95% of the nano-metal particles have a particle size variance ranging from 0.1 to 0.3.

[0019] The nano-metal particles in the nano-metal particle film are arranged in an array.

[0020] Furthermore, the transparent electrode is made of either IGZO or ITO.

[0021] Meanwhile, the present invention also provides a method for fabricating the above-mentioned photoelectric memristor based on plasma resonance enhanced absorption, which is characterized by including the following steps:

[0022] Step 1: Prepare an oxide, sulfide, or selenide defect-state semiconductor thin film of a first predetermined thickness on the upper surface of the substrate. By controlling the gas solubility of the oxide, sulfide, or selenide during the preparation process, the defect concentration of the defect-state semiconductor thin film is made to be 10. 16 -10 18 / cm 3 ;

[0023] Step 2: A metal thin film of a second predetermined thickness is sputtered onto the surface of the defect-state semiconductor thin film using magnetron sputtering to obtain a heterogeneous thin film structure;

[0024] Step 3: Place the heterogeneous thin film structure into a tube furnace for annealing. Under the action of its surface tension, the metal film condenses into nano-metal particles of different sizes, forming a nano-metal particle film.

[0025] Step 4: Prepare a transparent electrode with a third preset thickness on the surface of the nano-metal particle film;

[0026] Step 5: Prepare a metal electrode of a fourth predetermined thickness on the lower surface of the substrate to complete the fabrication of the photomemristor based on plasma resonance enhanced absorption.

[0027] Furthermore, in step 1, the first preset thickness is 1μm-5μm;

[0028] Methods for preparing defect-state semiconductor thin films on the upper surface of a substrate include magnetron sputtering, pulsed laser deposition, MOCVD, or vacuum thermal evaporation.

[0029] Furthermore, in step 2, the value range of the second preset thickness is 50 nm-300 nm;

[0030] In step 3, the annealing temperature is 500℃~800℃, and the annealing time is 1h~3h.

[0031] Furthermore, in step 4, the value range of the third preset thickness is 490nm-510nm;

[0032] In step 5, the fourth preset thickness ranges from 200nm to 500nm.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] 1. This invention discloses a photoelectric memristor based on plasma resonance enhanced absorption. Oxygen / sulfur / selenium vacancies in the defect-state semiconductor thin film can be tunably formed to form ion-conducting channels, while the nano-metal particle film utilizes its plasma resonance absorption characteristics to enhance the absorption capacity at specific wavelengths. Electrons generated by its plasma resonance are injected into the defect-state semiconductor thin film, which can realize the opening and closing of the ion-conducting channels, i.e., switching between high-resistance and low-resistance states. At the same time, by controlling the average particle size of the nano-metal particles in the nano-metal particle film to match the wavelength of the incident light, the wavelength absorption can be selective, which can cover more optical communication and imaging bands.

[0035] 2. The present invention provides a photoelectric memristor based on plasma resonance enhanced absorption. By setting transparent electrodes and nano-metal particle films, more wavelengths of visible light are incident on the photoelectric memristor, expanding the control capability of the memristor and enabling electro-optical synergistic modulation mode.

[0036] 3. The present invention provides a photoelectric memristor based on plasma resonance enhanced absorption. By setting a nano-metal particle film, the time for generating electrons based on plasma resonance absorption is on the order of fs-ps, which is much faster than the ion migration rate, thus significantly improving the response speed of the photoelectric memristor.

[0037] 4. The present invention provides a method for preparing a photoelectric memristor based on plasma resonance enhanced absorption. The method uses an annealing process to generate a nano-metal particle film, which is simple and can effectively reduce manufacturing costs. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of an embodiment of a photomemristor based on plasma resonance enhanced absorption according to the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the working principle of an embodiment of a photomemristor based on plasma resonance enhanced absorption according to the present invention.

[0040] The annotations in the attached figures are explained as follows:

[0041] 1. Metal electrode; 2. Substrate; 3. Defect-state semiconductor thin film; 4. Nanoscale metal particle film; 5. Transparent electrode. Detailed Implementation

[0042] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0043] like Figure 1-2 As shown, this embodiment provides a photoelectric memristor based on plasma resonance enhanced absorption, including a metal electrode 1, a substrate 2, a defect state semiconductor thin film 3, a nano metal particle film 4, and a transparent electrode 5 stacked sequentially from bottom to top;

[0044] An ohmic contact is formed between the metal electrode 1 and the substrate 2. The metal electrode 1 is made of one of gold, silver, copper, or aluminum, and its thickness is 200nm-500nm. The substrate 2 is made of one of Si, NSTO, or InP.

[0045] The defect-state semiconductor thin film 3 is an oxide, a sulfide, or a selenide, and its defect concentration is 10. 16 -10 18 / cm 3 The defect-state semiconductor thin film 3 is used to migrate and form a conductive channel after an external excitation electric field is applied, thereby realizing the switching of the resistance state of the defect-state semiconductor thin film 3; wherein, the resistance state includes a high resistance state and a low resistance state; the material of the defect-state semiconductor thin film 3 is one of ZnO, IGZO, SnO2, TiO2, WO3, MoS2, CdS, and CdSe.

[0046] The nano-metal particle film 4 is used to inject electrons generated by plasma resonance into the defect-state semiconductor thin film 3 after external light irradiation, thereby disrupting the conductive channels formed in the defect-state semiconductor thin film 3 and switching the resistive state of the defect-state semiconductor thin film 3. The average particle size of the nano-metal particles in the nano-metal particle film 4 is adapted to the wavelength of the external incident light, with the adaptation trend being that the wavelength of light becomes longer when the average particle size increases, and vice versa. Among them, 80%-95% of the nano-metal particles in the nano-metal particle film 4 have a particle size variance ranging from 0.1 to 0.3, and their material is one of gold, silver, platinum, and aluminum. The nano-metal particles in the nano-metal particle film 4 are arranged in an array. Depending on the different preparation processes, the generated nano-metal particle film 4 may be a regular array arrangement (photolithography) or an irregular arrangement.

[0047] The transparent electrode 5 is tightly bonded to the nano-metal particle film 4, and directly contacts the defect-state semiconductor thin film 3 at the gaps between the nano-metal particles, forming a good conductive path. The transparent electrode 5 is made of either IGZO or ITO.

[0048] Meanwhile, the present invention also provides a method for fabricating the above-mentioned photoelectric memristor based on plasma resonance enhanced absorption, comprising the following steps:

[0049] Step 1: Prepare an oxide, sulfide, or selenide defect-state semiconductor thin film 3 of a first predetermined thickness on the upper surface of substrate 2. By controlling the gas solubility of oxide, sulfide, or selenide during the preparation process, the defect concentration of the defect-state semiconductor thin film 3 is made to be 10. 16 -10 18 / cm 3 The first preset thickness is 1μm-5μm.

[0050] The method for preparing the defect-state semiconductor thin film 3 on the upper surface of the substrate 2 is magnetron sputtering, pulsed laser deposition, MOCVD, or vacuum thermal evaporation;

[0051] The defect-state semiconductor thin film 3 is made of one of ZnO, IGZO, SnO2, TiO2, WO3, MoS2, CdS, or CdSe.

[0052] Step 2: A metal thin film of a second preset thickness is sputtered on the surface of the defect state semiconductor thin film 3 using magnetron sputtering to obtain a heterostructure; wherein the value of the second preset thickness is in the range of 50 nm-300 nm.

[0053] Step 3: Place the heterogeneous thin film structure into a tube furnace for annealing. Under the action of its surface tension, the metal film condenses into nano-metal particles of different sizes to form nano-metal particle film 4. The annealing temperature is 500℃~800℃ and the annealing time is 1h~3h.

[0054] Step 4: Prepare a transparent electrode with a third preset thickness on the surface of the nano-metal particle film 4; wherein the value of the third preset thickness is in the range of 490nm-510nm.

[0055] Step 5: Prepare a metal electrode 1 with a fourth preset thickness on the lower surface of substrate 2 to complete the fabrication of the photoelectric memristor based on plasma resonance enhanced absorption. The value of the fourth preset thickness is in the range of 200nm-500nm.

[0056] In this embodiment, a ZnO defect-state semiconductor thin film 3 with a thickness of 2 μm and a defect concentration of 10 is first prepared on substrate 2 by magnetron sputtering. 18 / cm 3After sputtering a 100 nm Au metal film on the surface of the defect state semiconductor thin film 3, a high-temperature annealing process is performed at 600 degrees Celsius for 1 hour. Under the action of surface tension, the Au metal film condenses into a nano-metal particle film 4 with an average particle size of 300 nm. A 500 nm ITO transparent electrode 5 is then prepared on the surface of the nano-metal particle film 4. Finally, a 200 nm gold electrode is prepared on the bottom surface of the substrate 2.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A photoelectric memristor based on plasma resonance enhanced absorption, characterized in that: It includes a metal electrode (1), a substrate (2), a defect-state semiconductor thin film (3), a nano-metal particle film (4), and a transparent electrode (5) stacked sequentially from bottom to top. An ohmic contact is formed between the metal electrode (1) and the substrate (2); The defect-state semiconductor thin film (3) is an oxide, a sulfide, or a selenide, and its defect concentration is 10. 16 -10 18 / cm 3 The defect-state semiconductor thin film (3) is used to migrate its internal defects to form a conductive channel after an external excitation electric field is applied, thereby realizing the switching of the resistance state of the defect-state semiconductor thin film (3); the resistance state includes a high resistance state and a low resistance state. The nano-metal particle film (4) is used to inject electrons generated by plasma resonance into the defect state semiconductor film (3) after external light irradiation is applied, so as to destroy the conductive channel formed in the defect state semiconductor film (3) and switch the resistance state of the defect state semiconductor film (3); the average particle size of the nano-metal particles in the nano-metal particle film (4) is adapted to the wavelength of the external incident light. The transparent electrode (5) is closely bonded to the nano-metal particle film (4) and directly contacts the defect-state semiconductor film (3) at the gap between each nano-metal particle to form a conductive path.

2. The photomemristor based on plasma resonance enhanced absorption according to claim 1, characterized in that: The metal electrode (1) is made of one of the following materials: gold, silver, copper, and aluminum; The thickness of the metal electrode (1) is 200nm-500nm.

3. The photomemristor based on plasma resonance enhanced absorption according to claim 1, characterized in that: The substrate (2) is made of one of Si, NSTO, or InP. The defect state semiconductor thin film (3) is made of one of ZnO, IGZO, SnO2, TiO2, WO3, MoS2, CdS, or CdSe.

4. The photomemristor based on plasma resonance enhanced absorption according to claim 1, characterized in that: The nano-metal particle film (4) is made of one of the following materials: gold, silver, platinum, and aluminum.

5. The photomemristor based on plasma resonance enhanced absorption according to claim 4, characterized in that: In the nano-metal particle film (4), 80%-95% of the nano-metal particles have a particle size variance ranging from 0.1 to 0.

3. The nano-metal particles in the nano-metal particle film (4) are arranged in an array.

6. The photomemristor based on plasma resonance enhanced absorption according to claim 1, characterized in that: The transparent electrode (5) is made of either IGZO or ITO.

7. A method for fabricating a photomemristor based on plasma resonance enhanced absorption as described in claim 1, characterized in that, Includes the following steps: Step 1: Prepare an oxide, sulfide, or selenide defect-state semiconductor thin film (3) of a first predetermined thickness on the upper surface of the substrate (2). By controlling the gas solubility of oxide, sulfide, or selenide during the preparation process, the defect concentration of the defect-state semiconductor thin film (3) is made to be 10. 16 -10 18 / cm 3 ; Step 2: A metal film of a second preset thickness is sputtered on the surface of the defect-state semiconductor thin film (3) using magnetron sputtering to obtain a heterogeneous thin film structure; Step 3: The heterogeneous thin film structure is placed in a tube furnace for annealing. Under the action of its surface tension, the metal film condenses into nano-metal particles of different sizes to form a nano-metal particle film (4). Step 4: Prepare a transparent electrode (5) with a third preset thickness on the surface of the nano-metal particle film (4); Step 5: Prepare a metal electrode (1) of a fourth preset thickness on the lower surface of the substrate (2) to complete the fabrication of the photoelectric memristor based on plasma resonance enhanced absorption.

8. The method for fabricating a photomemristor based on plasma resonance enhanced absorption according to claim 7, characterized in that, In step 1, the first preset thickness is 1μm-5μm; The method for preparing a defect-state semiconductor thin film (3) on the upper surface of the substrate (2) is magnetron sputtering, pulsed laser deposition, MOCVD, or vacuum thermal evaporation.

9. The method for fabricating a photomemristor based on plasma resonance enhanced absorption according to claim 7, characterized in that: In step 2, the value range of the second preset thickness is 50 nm-300 nm; In step 3, the annealing temperature is 500℃~800℃, and the annealing time is 1h~3h.

10. The method for fabricating a photomemristor based on plasma resonance enhanced absorption according to claim 7, characterized in that: In step 4, the value range of the third preset thickness is 490nm-510nm; In step 5, the fourth preset thickness ranges from 200nm to 500nm.

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