A multi-electrode coupled optoelectronic device, and a method of manufacturing and use thereof

Abstract

This invention provides a multi-electrode coupled optoelectronic device, comprising a bottom electrode made of a low work function metal, a p-type semiconductor layer with light-absorbing function disposed on the upper surface of the bottom electrode, a thin insulating layer disposed on the upper surface of the light-absorbing p-type semiconductor layer, an n-type semiconductor layer with light-absorbing function disposed on the surface of the insulating layer, a top electrode made of a high work function metal and at least one auxiliary electrode disposed on the upper surface of the light-absorbing n-type semiconductor layer. This invention also provides a method for fabricating the multi-electrode coupled optoelectronic device and its application.

Description

Technical Field

[0001] This application belongs to the field of optoelectronic device technology, and more specifically, relates to the application of a multi-electrode coupled optoelectronic device and its fabrication method. Background Technology

[0002] Photodetectors have been deeply integrated into numerous fields such as imaging, communication, manufacturing, scientific research, medicine, and defense. Scenarios such as artificial intelligence, precision medicine, and large-scale industrial control pose unprecedented challenges to the precision, integration, and miniaturization of devices, driving researchers to race to develop next-generation optoelectronic sensing chips with wide-spectrum response, high sensitivity, low cost, and high performance. Achieving high sensitivity, wide spectral coverage, weak light resolution, high dynamic range, ultrafast response, high photocurrent responsivity, ultra-high external quantum efficiency, and excellent specific detectivity remains the ultimate goal pursued by scientists and engineers. However, most traditional optoelectronic devices are currently limited by their intrinsic device structure, making it difficult to simultaneously achieve high-efficiency optoelectronic performance in all aspects. The core strategy lies in precisely suppressing dark current while synergistically amplifying photocurrent, thereby achieving the optimal balance to maximize overall performance. On the one hand, as a key performance indicator, dark current has a decisive impact on many optoelectronic properties such as on / off ratio, stability, photoresponse, external quantum efficiency, and specific detectivity, ultimately limiting the overall performance of the device. Summary of the Invention

[0003] In view of the shortcomings of traditional technologies, the purpose of this application is to provide a multi-electrode coupled optoelectronic device and its fabrication method, which aims to solve the technical problem that existing optoelectronic devices are prone to high dark current or low photocurrent under traditional structural paradigms, which prevents the overall improvement of the optoelectronic performance of the device.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A multi-electrode coupled optoelectronic device includes a bottom electrode made of a metal with a work function of less than 4.82 eV, a p-type semiconductor layer with light-absorbing function on the upper surface of the bottom electrode, a thin insulating layer on the upper surface of the p-type semiconductor layer with light-absorbing function, an n-type semiconductor layer with light-absorbing function on the surface of the thin insulating layer, a top electrode made of a metal with a work function of more than 4.16 eV and at least one auxiliary electrode on the upper surface of the n-type semiconductor layer with light-absorbing function.

[0005] The p-type semiconductor layer includes a boron-doped silicon wafer; The n-type semiconductor layer includes zinc oxide, TiO2, IGZO, ITZO, IZO, or SnO2; The bottom electrode includes an aluminum electrode or a silver electrode; The top electrode includes a gold electrode or a platinum electrode; The auxiliary electrode includes a gold electrode, an aluminum electrode, or a silver electrode.

[0006] The thickness of the bottom electrode is 3-300 nm; The thickness of the p-type semiconductor layer is 200-2000µm; The thickness of the n-type semiconductor layer is 10nm-500nm; The thickness of the top electrode is 5nm~500nm; The thickness of the auxiliary electrode is 5nm to 500nm.

[0007] The thin insulating layer includes aluminum oxide, silicon dioxide, hafnium dioxide, or zirconium dioxide.

[0008] The method for fabricating the multi-electrode coupled optoelectronic device includes the following steps: S1 deposits a bottom electrode on the surface of the p-type semiconductor layer; S2 deposits an insulating layer on the surface of the p-type semiconductor layer away from the bottom electrode; S3 deposits an n-type semiconductor layer on the surface of the insulating layer away from the p-type semiconductor layer; S4 deposits a top electrode and an auxiliary electrode on the surface of the n-type semiconductor layer away from the insulating layer, thus obtaining the desired result.

[0009] The thickness of the thin insulating layer is 1-15 nm.

[0010] The horizontal distance between the top electrode and the auxiliary electrode is 2-120µm; The width of the top electrode is 0.1-3 mm; The width of the auxiliary electrode is 0.1-3 mm.

[0011] The deposition is selected from one or more of magnetron sputtering, evaporation, chemical vapor deposition, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, metal compound vapor deposition, molecular beam epitaxy, atomic vapor deposition, atomic layer deposition, or electron beam grazing angle deposition.

[0012] The aforementioned multi-electrode coupled optoelectronic device is used in the fabrication of imaging or communication equipment.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: In the multi-electrode coupled optoelectronic device provided by this invention, a Schottky barrier is formed between the bottom electrode and the p-type semiconductor layer with light-absorbing function, and a Schottky barrier is also formed between the top electrode and the auxiliary electrode and the n-type semiconductor layer with light-absorbing function. The core of this multi-electrode design lies in "energy level alignment and electric field redistribution caused by multiple electrodes". This design can significantly suppress the dark current of the photodetector and enhance the photocurrent.

[0014] More importantly, compared to existing optoelectronic devices with only a bottom electrode and a top electrode, this invention introduces an auxiliary electrode, which can be made to float (i.e., this causes different charge distributions among the multiple electrodes, resulting in changes in the internal electric field strength of the device, and consequently, changes in the device's photoelectric effect). Specifically, when the auxiliary electrode is floated, the top electrode is connected to 0 voltage, and the bottom electrode is connected to a positive voltage, the distance between the multiple electrodes at the top is relatively close. Therefore, through semiconductor polarization, the coupling effect generated between the top electrode and the auxiliary electrode is stronger than the coupling effect between the bottom electrode and the top electrode when they are connected in wire.

[0015] Simultaneously, in the vertical direction, due to the double-gate Schottky barrier, when the bottom electrode voltage increases, the electric field strength between the top electrode and the auxiliary electrode is much higher than that between the bottom and top electrodes connected in the vertical direction. Under the synergistic effect of the double-gate Schottky barrier, the vertical dark current is effectively suppressed. Furthermore, the increased electric field strength in the horizontal direction, especially when within the light field region, leads to charge transfer between the top electrode and the auxiliary electrode upon illumination, forming a larger effective electric field region and generating a larger photocurrent.

[0016] In summary, the multi-electrode coupled optoelectronic device provided by this invention can improve the overall optoelectronic performance of the device without increasing its size or external conditions.

[0017] By introducing the Schottky barrier difference and a thin insulating layer of alumina, and through the synergistic effect of the terminal voltage and photoelectric field, and by real-time rearranging of space charge and electric field lines (the electric field always tends towards a path where "work is done faster and there is less resistance"), and by shifting the electric field lines from a predominantly lateral distribution to a longitudinal distribution under illumination, it is possible to achieve nA-level dark current and µA-level photocurrent. 3 The contrast is significantly enhanced. Clearly, under the combined effect of these factors, the overall photoelectric performance of the multi-electrode coupled optoelectronic device provided by this invention is greatly improved.

[0018] The multi-electrode coupled optoelectronic device provided by this invention can generate different photocurrents for incident light with different optical power densities, and has a fast and stable optical response to incident light of different wavelengths, exhibiting high sensitivity to weak light intensity. Specifically, a three-electrode coupled optoelectronic device provided in a certain embodiment of this invention achieves a photocurrent of 0.45 nW / cm² in a wide wavelength range of 365–1100 nm. 2It exhibits high sensitivity in low light conditions. With an applied bias of 10 volts, the device achieves an ultra-low dark current of only 2.95 × 10⁻⁶. -9 Ampere. Under 5 volt bias and low-intensity illumination (0.688 μW / cm²). 2 Under these conditions, its photocurrent responsivity reaches as high as 662 A / W, and its specific detectivity reaches 2.15 × 10⁻⁶. 16 Jones has an external quantum efficiency of 2252%, a light-to-dark current ratio of 310, and switching rise / fall times of 0.10 / 0.11 seconds, respectively.

[0019] The method for fabricating multi-electrode coupled optoelectronic devices provided by this invention is simple, low-cost, and suitable for large-scale production.

[0020] Because the multi-electrode coupled optoelectronic device provided by this invention has excellent optoelectronic performance, it has broad application prospects in many fields such as imaging, communication, manufacturing, scientific research, medical treatment and national defense. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure of the three-electrode coupled optoelectronic device provided in an embodiment of the present invention is shown; Wherein: 101 is an aluminum electrode, 102 is a highly doped silicon wafer, 103 is an aluminum oxide layer, 104 is a light-absorbing zinc oxide film, 105 is a metal electrode, and 106 is an auxiliary electrode.

[0022] Figure 2 The photoresponse IV principle of the three-electrode coupled optoelectronic device in the embodiments of this application is illustrated; Figure 3 The It curves of the three-electrode coupled optoelectronic device in the embodiments of this application are shown under different optical power densities at a light wavelength of 365nm. Figure 4 The three-dimensional current responsivity diagram of the three-electrode coupled optoelectronic device in the embodiment of this application under different voltages and different optical power densities at a 365nm light wavelength is shown. Figure 5 The embodiment of this application shows a three-electrode coupled optoelectronic device with a light wavelength of 365 nm and an optical power density of 84.03 µW / cm². 2 On / off response time under certain conditions. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] The relentless pursuit of high-performance optoelectronic devices is driving advancements in intelligent sensing, autonomous systems, and next-generation optical communication networks. (In over 10...) 3 The synchronous achievement of A / W responsiveness, fast dynamic response, and near-zero dark current constitutes a crucial and ongoing challenge.

[0025] Traditional two-terminal device architectures (photoconductors, photodiodes, and phototransistors), due to their inherent structural limitations, struggle to synergistically suppress dark current while simultaneously amplifying photocurrent, thus hindering overall improvement in device optoelectronic performance. These limitations force a fundamental and often insurmountable trade-off between photoconductive gain and noise suppression.

[0026] For example, photoconductors typically exhibit high current responsivity, high quantum efficiency, and large gain, but these advantages are offset by significant dark current caused by terminal voltage and relatively slow switching response time caused by large electrode spacing.

[0027] Furthermore, traditional photodiodes possess high modulation rates, fast switching responses, and large dynamic ranges, but their limitations lie in relatively low quantum efficiency and current responsivity. Phototransistors exhibit high current responsivity and can effectively improve the collection efficiency of photogenerated carriers by modulating the semiconductor channel with gate voltage; however, they also face problems such as slow response speed and dark current. Based on this, the present invention provides a three-electrode coupled optoelectronic device, such as... Figure 1 As shown, it includes a bottom electrode layer, a p-type semiconductor layer with light-absorbing function disposed on the upper surface of the bottom electrode layer (in a specific embodiment of the present invention, it is a boron-doped silicon wafer), an insulating layer disposed on the surface of the p-type semiconductor layer (in a specific embodiment of the present invention, it is an aluminum oxide layer), an n-type semiconductor layer with light-absorbing function disposed on the surface of the insulating layer (in a specific embodiment of the present invention, it is a zinc oxide layer), and a top electrode and an auxiliary electrode covering the upper surface of the n-type semiconductor layer.

[0028] In a three-electrode coupled optoelectronic device provided in a certain embodiment of the present invention, when the n-type semiconductor is a zinc oxide layer, the p-type semiconductor is a boron-doped silicon wafer, the bottom electrode is aluminum, and the top electrode and auxiliary electrode are gold, it is based on ZnO / Au and Al / p-Si Schottky contacts, quasi-Schottky contacts, or ohmic contacts.

[0029] When the bottom electrode of a ZnO / Au or Al / p-Si device is positively voltaged, the presence of the Schottky barrier somewhat suppresses the current. When the top and bottom electrodes are connected, and the bottom electrode is set to a positive voltage, a transverse electric field exists between the auxiliary electrode and the top electrode when the device is not illuminated. This field simultaneously shares the vertical electric field lines, thus weakening the electric field strength and reducing the dark current. Furthermore, when the illumination intensity is zero, only the top and bottom electrodes generate dark current. When light illuminates the channel between the top electrodes, the light-absorbing material between the channels generates a certain density of photogenerated carriers, increasing conductivity and causing the top electrode and auxiliary electrode to form a large "top electrode," thereby increasing the photocurrent. Therefore, this three-electrode coupled optoelectronic device exhibits high performance, fast response, and high stability photoelectric response performance.

[0030] Furthermore, by inserting an insulating layer (specifically an aluminum oxide layer) between the boron-doped silicon wafer and the zinc oxide layer, the dark current of the device can be further suppressed.

[0031] In some embodiments, the aforementioned bottom aluminum electrode can be a metal with a lower work function, such as calcium. A low work function refers to the work function of a metal that can form a Schottky barrier with a p-type semiconductor as much as possible.

[0032] In some embodiments, the thickness of the p-type semiconductor layer is 450 nm to 2 mm.

[0033] In some embodiments, the thickness of the insulating layer is 1 nm to 15 nm.

[0034] In some embodiments, the thickness of the n-type semiconductor layer is 10 nm to 500 nm. In some embodiments, the dual electrodes can be the same gold metal electrode or different metal electrodes with high work functions. A high work function is the work function of the metal that can form a relatively high barrier with the n-type semiconductor.

[0035] In some embodiments, the light-absorbing n-type semiconductor layer is selected from any one of TiO2, ZnO, and SnO2.

[0036] This invention also provides a specific method for fabricating a three-electrode coupled optoelectronic device (the method for fabricating a multi-electrode coupled optoelectronic device is similar), comprising the following steps: An aluminum electrode layer is deposited on one side of a boron-doped silicon wafer. An alumina layer is prepared on the other side using atomic layer deposition. A zinc oxide film is then prepared on the surface of the alumina layer using a solution method. Alternatively, the zinc oxide film can be prepared directly on the surface of the boron-doped silicon wafer without preparing an alumina layer.

[0037] A metal top electrode and an auxiliary electrode are deposited on the surface of a zinc oxide film, with a distance of 2-120 µm between the electrodes and an electrode width of 0.1-3 mm, resulting in a three-electrode coupled optoelectronic device. In this invention, the metal used to fabricate the bottom electrode needs to form a certain Schottky barrier with the semiconductor to suppress dark current to a certain extent.

[0038] The present invention does not limit the method for preparing the bottom electrode or top electrode and the insulating layer, including but not limited to magnetron sputtering, evaporation, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), metal compound vapor deposition (MOCVD), molecular beam epitaxy (MBE), atomic vapor deposition (AVD), atomic layer deposition (ALD), and electron beam grazing angle deposition (GLAD).

[0039] In certain embodiments of the present invention, a semiconductor heterojunction layer can be prepared by coating a colloidal solution of TiO2, ZnO, or SnO2 materials onto the surface of a p-type semiconductor layer. The coating rotation speed is 2000 rpm to 8000 rpm, and the coating time is 30 s to 60 s. It should be understood that appropriately increasing / decreasing the coating rotation speed and extending / shortening the coating time according to actual conditions are also within the scope of protection of this application.

[0040] The above technical solution will be described in detail below with reference to specific embodiments. Example 1

[0041] like Figure 1 As shown, this embodiment provides a three-electrode coupled optoelectronic device, which sequentially includes a bottom electrode aluminum electrode layer (101), a boron-doped silicon wafer (102), an aluminum oxide film (103), a zinc oxide film (104), a gold electrode (105) as the top electrode, and a gold electrode (106) as the auxiliary electrode.

[0042] In this embodiment, the aluminum electrode film (101) has a thickness of 7 nm.

[0043] In this embodiment, the boron-doped silicon wafer (102) has a thickness of 450µm.

[0044] In this embodiment, the zinc oxide layer (103) has a thickness of 28 nm. During preparation, zinc oxide is dissolved in ammonia water, stirred for 3 hours, and filtered through a 0.45 µm filter to obtain a clear solution. The clear zinc oxide solution is then spin-coated onto a clean alumina layer at 3000 rpm, followed by annealing at 300°C for 1 hour to obtain a zinc oxide film (104).

[0045] In this embodiment, the top electrode and auxiliary electrode are made of gold, and the thickness of the two top electrode films is 30 nm. The top electrode is 2 mm long, the gold electrode is 0.5 mm wide, and the distance between the gold electrodes is 100 µm.

[0046] The fabrication method of the three-electrode coupled optoelectronic device provided in this embodiment will be described below: (1) Cleaning of boron-doped silicon wafer substrate The p-doped boron silicon substrate was cut into 11×11mm pieces, and ultrasonically cleaned in sequence with acetone, isopropanol, deionized water and ethanol for 20 minutes. It was then dried with nitrogen and baked in an oven at 70℃ for 2 hours for later use.

[0047] (2) Preparation of aluminum electrode A 300 nm thick aluminum electrode is vacuum-deposited on one side of a p-doped boron silicon wafer.

[0048] (3) To prepare the alumina layer, the silicon wafer needs to be irradiated with ultraviolet light for more than 30 minutes, and then subjected to 30 cycles of atomic layer deposition (ALD) on the polished surface of the silicon wafer at 150°C and 1 Pa. One ALD cycle includes: TMA 0.02 s → N2 8 s → Ar 25 s → H2O 0.1 s → N2 8 s → Ar 30 s. A highly uniform Al2O3 film with a thickness of N × 0.7 Å is obtained. After 30 cycles, an alumina film (103) with a thickness of 2.2 nm is obtained.

[0049] (4) Preparation of zinc oxide film Prepare an 8 mg / mL zinc oxide ammonia solution and stir for at least 12 hours. Filter the zinc oxide solution through a 0.45 µm filter to obtain a clear solution, and spin-coat it onto the other side of the boron-doped silicon substrate loaded with an alumina film at 3000 rpm for 30 seconds, then heat at 300 °C for 60 minutes.

[0050] (5) Fabrication of Au metal top electrode and auxiliary electrode A cleaned substrate is attached to a photomask using high-temperature conductive adhesive. Au metal is then deposited using a vacuum evaporation system. The deposited double gold electrodes are 0.5 mm wide and 2 mm long, with a spacing of 100 µm between them, resulting in a three-electrode coupled photodetector. Figure 1 As shown.

[0051] Specifically, the three-electrode coupled optoelectronic device provided in this embodiment can be used as follows: The bottom and top electrodes maintain a voltage difference, while the auxiliary electrode is either suspended or connected. Using the method of connecting the top electrode to 0 voltage, suspending the auxiliary electrode, and connecting the bottom electrode, and performing voltage testing in the range of -5 to 10 V, when using the three-electrode coupled optoelectronic device prepared in this embodiment, the ultraviolet light power density at a wavelength of 365 nm is increased from 0 nW / cm². 2 Adjusted to 0.688µW / cm 2 IV curves for different optical power densities can be obtained (e.g.) Figure 2 ) and It curve (such as Figure 3 As shown in the figure.

[0052] Figure 4 The current responsivity surface plots of the three-electrode coupled photodetector prepared for the example are shown under different voltage and optical power density conditions.

[0053] Figure 5 The three-electrode coupled photodetector prepared for this example achieved an optical power density of 84.03 nW / cm² at a bottom electrode voltage of 5V. 2 As shown in the figure, the It curve for a single cycle indicates that the switching response time of the three-electrode coupled photodetector prepared in the example is 0.10 / 0.11s.

[0054] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-electrode coupled optoelectronic device, characterized in that: It includes a bottom electrode made of a metal with a work function of less than 4.82 eV, and a p-type semiconductor layer with light-absorbing function on the upper surface of the bottom electrode; a thin insulating layer on the upper surface of the p-type semiconductor layer with light-absorbing function; an n-type semiconductor layer with light-absorbing function on the surface of the thin insulating layer; a top electrode made of a metal with a work function of more than 4.16 eV and at least one auxiliary electrode on the upper surface of the n-type semiconductor layer with light-absorbing function.

2. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that: The p-type semiconductor layer includes a boron-doped silicon wafer; The n-type semiconductor layer includes zinc oxide, TiO2, IGZO, ITZO, IZO, or SnO2; The bottom electrode includes an aluminum electrode or a silver electrode; The top electrode includes a gold electrode or a platinum electrode; The auxiliary electrode includes a gold electrode, an aluminum electrode, or a silver electrode.

3. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that: The thickness of the bottom electrode is 3-300 nm; The thickness of the p-type semiconductor layer is 200-2000µm; The thickness of the n-type semiconductor layer is 10nm-500nm; The thickness of the top electrode is 5nm~500nm; The thickness of the auxiliary electrode is 5nm~500nm.

4. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that: The thin insulating layer is Al2O3, zirconium oxide, silicon dioxide, or hafnium oxide.

5. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that: The thickness of the thin insulating layer is 1-15 nm.

6. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that: The horizontal distance between the top electrode and the auxiliary electrode is 2-120µm; The width of the top electrode is 0.1-3 mm.

7. The multi-electrode coupled optoelectronic device according to claim 1, characterized in that, Includes the following steps: The width of the auxiliary electrode is 0.1-3 mm.

8. The method for fabricating a multi-electrode coupled optoelectronic device according to claim 4, characterized in that, Includes the following steps: S1 deposits a bottom electrode on the surface of the p-type semiconductor layer; S2 deposits a thin insulating layer on the surface of the p-type semiconductor layer away from the bottom electrode; S3 deposits an n-type semiconductor layer on the surface of the thin insulating layer away from the p-type semiconductor layer; S4 deposits a top electrode and an auxiliary electrode on the surface of the n-type semiconductor layer away from the thin insulating layer, thus obtaining the desired result.

9. The method for fabricating a multi-electrode coupled optoelectronic device according to claim 8, characterized in that: The deposition is selected from one or more of magnetron sputtering, evaporation, chemical vapor deposition, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, metal compound vapor deposition, molecular beam epitaxy, atomic vapor deposition, atomic layer deposition, or electron beam grazing angle deposition.

10. The application of the multi-electrode coupled optoelectronic device according to claim 1, characterized in that: It can be used to manufacture photoelectric detection or photoelectric switching devices, as well as imaging or communication equipment.

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