A low-power single-row carrier photodetector and its preparation method

Abstract

The application discloses a low-power single-carrier photoelectric detector and a preparation method thereof. The detector adopts a GaAsSb / InP material system, and the detector comprises, from top to bottom, a P-type contact layer, a blocking layer, an absorption layer, a depletion absorption layer, a cliff layer, a collection layer, an N-type auxiliary collection layer, an N-type contact layer and a substrate. The device has the advantages of high responsivity and low preparation difficulty.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detectors, and in particular to a low-power single-row carrier photoelectric detector and a preparation method thereof. Background Art

[0002] As the final component in an optical communication link, a photodetector connects photonic integrated circuits and traditional integrated circuits. Its bandwidth determines the data detection rate limit of the entire photonic link, while its output RF power influences the bit error rate of the subsequent decision-making circuits. Generally, these conflicting performance characteristics of bandwidth and RF output power are adjusted within a target range based on requirements.

[0003] Traditional photodetectors are PIN photodetectors (Positive-Intrinsic-Negative Photodiode, PIN-PD). The intrinsic absorption layer simultaneously absorbs photons and generates a depletion region. Photogenerated electrons and holes simultaneously participate in the generation of photocurrent, resulting in the slower hole speed limiting the upper limit of bandwidth performance. In 1997, T. Ishibashi et al. at NTT Photonics Laboratories in Japan proposed the Uni-Traveling-Carrier Photodetector (UTC-PD). Using electrons as the sole carrier, it effectively increases carrier transmission speed, suppresses space charge effects, and improves the bandwidth and RF output power of the photodetector. In addition, the separation of the absorption and depletion regions allows the carrier transit time and RC constant to be independently designed to a certain extent.

[0004] UTC-PD has been applied in different wavelength bands, and 1550 nm band has become one of the common bands in optical fiber communication due to its low propagation loss in optical fiber. The material system used in this band is usually InGaAs / InP system. InGaAs and InP have the advantage of high mobility, which is of great significance to the inhibition of space charge effect. In the high-speed direction, the highest bandwidth has reached 310 GHz, while in the high-power direction, the highest performance can reach 32.3 dBm@10 GHz. However, InGaAs / InP is a type I heterojunction with a conduction band difference of 0.21 eV. When the electron is pumped from the absorption layer to the collection layer, it must cross the conduction band peak formed by the two materials, and special attention should be paid to the smoothing of the conduction band in the case of ultra-high speed and high incident optical power. GaAsSb / InP is a type II heterojunction without conduction band peak. The conduction band of GaAsSb is 0.11 eV higher than that of InP, so the electron injection from the absorption layer GaAsSb to the collection layer InP has an acceleration effect. And the imaginary part of the refractive index of GaAsSb is higher than that of InGaAs (0.201 and 0.09), which means that the responsivity of the PD with GaAsSb as the absorption layer is higher. Unfortunately, the mobility of GaAsSb is lower than that of InGaAs. At a doping concentration of 2×10 17 cm -3 , the mobility of the latter is nearly twice that of the former, resulting in a smaller electron drift velocity. Therefore, it is very important to properly select the material and give full play to its performance advantages.

[0005] Currently, UTC-PDs based on the GaAsSb / InP system primarily utilize the lack of conduction band spikes and electron acceleration in the type-II heterojunction to achieve high-speed UTC-PDs. Although GaAsSb has low electron mobility, the absorption layer of high-speed PDs is thin (around 100nm), and the electrons in the depletion region, which accounts for approximately 50% of the absorption layer, are primarily drift-prone, thus having little impact on mobility. In 2005, LG Zheng et al. fabricated a UTC-PD with a 100nm absorption layer and a 200nm collection layer. When the diameter is 9.5μm, the 3dB bandwidth exceeds 50GHz. It is estimated that the carrier transit time of the PD limits the bandwidth to 105GHz; in 2013, Ge Zang et al. increased the 3dB bandwidth to 106.6GHz by optimizing the doping distribution of the absorption layer and giving corresponding simulation results; in 2018, QH Yu et al. prepared a barrier-free UTC-PD with an absorption layer of 250nm and a collection layer of 350nm. The 3dB bandwidth tested under zero bias exceeded 40GHz, and the output power reached -2.8dBm; in 2021, Jesse S. Morgan et al. prepared a UTC-PD with an absorption layer of 100nm and a collection layer of 250nm. The 3dB bandwidth reached 125GHz under a bias of -1.1V, and the frequency roll-off at 325GHz was 12dB; in 2023, Christopher Coleman et al. made an integrated data receiving system with UTC-PD as the core, and the 3dB bandwidth of the system can reach 220GHz.

[0006] GaAsSb / InP system materials have not yet been applied in the high-power direction. Although the lower mobility will impose certain limitations on bandwidth and output power, the type II heterojunction has no conduction band peak that hinders electron pumping, which can eliminate the need for a quaternary transition layer and reduce the difficulty of epitaxy. Secondly, the absorption coefficient of GaAsSb is higher than that of InGaAs, and a higher responsivity can be achieved in a thinner thickness. At the same output current, GaAsSb requires less incident light power. The incident light of a high-power PD needs to be amplified to hundreds to thousands of milliwatts by an EDFA. From the perspective of energy consumption, GaAsSb is a better choice. Summary of the Invention

[0007] To address the technical problems of low responsivity and high difficulty in device preparation in the prior art high-speed, high-power single-row carrier photodetectors, the present invention provides a low-power single-row carrier photodetector and a method for preparing the same. The technical solution adopted by the invention is:

[0008] The first aspect of the present invention provides a low-power single-row carrier photodetector, which adopts a GaAsSb / InP material system. The detector comprises, from top to bottom, a P-type contact layer, a barrier layer, an absorption layer, a depletion absorption layer, a cliff layer, a collection layer, an N-type sub-collection layer, an N-type contact layer and a substrate.

[0009] As a preferred solution, the material of the P-type contact layer is p-type heavily doped In 0.53 Ga 0.47 As material.

[0010] As a preferred solution, the material of the barrier layer is p-type heavily doped Al 0.3 Ga 0.7 As 0.5 Sb 0.5 Material.

[0011] As a preferred solution, the material of the absorption layer adopts p-type four-level stepped heavily doped narrow-bandgap GaAsSb material, and the absorption layer includes a first absorption layer, a second absorption layer, a third absorption layer and a fourth absorption layer from top to bottom. The concentration gradient of the first absorption layer, the second absorption layer, the third absorption layer and the fourth absorption layer is within a preset range.

[0012] As a preferred solution, the depletion absorption layer is made of n-type lightly doped GaAsSb material.

[0013] As a preferred solution, the cliff layer is made of n-type heavily doped InP material.

[0014] As a preferred solution, the collection layer is made of lightly doped InP material, and the collection layer has an electric field with a preset field strength to reduce junction capacitance and maintain the overshoot speed of electrons in the collection layer.

[0015] As a preferred solution, the material of the N-type sub-collection layer is n-type heavily doped InP material.

[0016] As a preferred solution, the material of the N-contact layer is n-type heavily doped InP material.

[0017] A second aspect of the present invention provides a method for preparing a low-power single-row carrier photodetector, comprising the following steps:

[0018] S1: Using metal organic compound chemical vapor deposition technology, an N-type contact layer, an N-type sub-collection layer, a collection layer, a cliff layer, a depletion absorption layer, an absorption layer, a barrier layer, and a P-type contact layer are grown in sequence from bottom to top on a semi-insulating substrate to obtain a complete epitaxial wafer;

[0019] S2: Use a maskless UV lithography machine to expose the circular P electrode pattern and alignment marks, and perform surface acid treatment to form a good ohmic contact;

[0020] S3: P electrode is deposited using electron beam evaporation equipment and lift-off is performed using acetone solution;

[0021] S4: Spin-coat HSQ negative resist, overlay the P mesa using an electron beam lithography device, then dry-etch the P mesa using an inductively coupled plasma etching system until the N-type contact layer is reached, and then cleanly etch the HSQ negative resist using a reactive ion beam etching system.

[0022] S5: Expose the N mesa pattern using a maskless UV lithography machine, and etch the InP to the semi-insulating substrate using HCl:H2O=1:1 to form the N mesa, and then remove the resist by bombarding with acetone solution and oxygen plasma;

[0023] S6: Use a maskless UV lithography machine to expose the full electrode pattern and perform surface acid treatment to form a good ohmic contact;

[0024] S7: Full electrode evaporation is performed using an electron beam evaporation device, and lift-off is performed using an acetone solution, and finally rapid thermal annealing is performed to obtain the low-power single-row carrier photodetector.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The purpose of this invention is to optimize and innovate the epitaxial layer based on the existing high-speed and high-power single-line carrier photodetector structure, introduce the GaAsSb / InP material system for the first time, and make the absorption layer In 0.57 Ga 0.43 As is replaced with GaAs that matches the InP lattice 0.51 Sb 0.49 , which improves the responsiveness of the device and reduces the energy consumption of EDFA in the optical fiber communication system; at the same time, the type II heterojunction formed by the GaAsSb / InP material system introduced in the present invention does not have a conduction band peak, which can avoid the epitaxy of the traditional InGaAsP quaternary component transition layer and reduce the difficulty of device epitaxy to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a low-power single-row carrier photodetector provided in this embodiment;

[0028] Figure 2 Schematic diagram of the heterojunction energy bands of the device of the present invention (absorption layer 150nm + depletion absorption layer 150nm + collection layer 600nm) and the UTC-PD of the InGaAs / InP material system (absorption layer 150nm + depletion absorption layer 150nm + collection layer 600nm), wherein the conduction band of the latter has an energy band peak;

[0029] Figure 3Schematic diagram of the epitaxial layers of the device of the present invention (absorption layer 150nm + depletion absorption layer 150nm + collection layer 600nm) and the UTC-PD (absorption layer 150nm + depletion absorption layer 150nm + collection layer 600nm) of the InGaAs / InP material system provided in this embodiment, where the mesa diameter of both PDs is 28μm;

[0030] Figure 4 Two-dimensional device simulation diagrams of the device of the present invention (150nm absorption layer + 150nm depletion absorption layer + 600nm collection layer) and the UTC-PD (150nm absorption layer + 150nm depletion absorption layer + 600nm collection layer) of the InGaAs / InP material system provided in this embodiment (Figure a is a diagram of the carrier transit time limited bandwidth, and Figure b is a diagram of the saturated output current);

[0031] Figure 5 Two-dimensional device simulation diagrams of the device of the present invention (absorption layer 150nm + depletion absorption layer 150nm + collection layer 600nm) and the UTC-PD ((absorption layer + depletion absorption layer) 630nm + collection layer 600nm) of the InGaAs / InP material system provided in the examples;

[0032] Figure 6 Schematic diagram of the epitaxial layer of the device structure of the present invention provided in the embodiment (PD1 is an absorption layer of 150nm + a depletion absorption layer of 150nm + a collection layer of 600nm, with a mesa diameter of 28μm; PD2 is an absorption layer of 200nm + a depletion absorption layer of 200nm + a collection layer of 800nm, with a mesa diameter of 34μm);

[0033] Figure 7 The carrier transit time limit bandwidth diagram of PD1 and PD2 provided in this embodiment;

[0034] Figure 8 The junction capacitance-cathode bias diagram of PD1 and PD2 provided in this embodiment;

[0035] Figure 9 This is a diagram of the saturated output current of PD1 and PD2 provided in this embodiment. DETAILED DESCRIPTION

[0036] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting the present invention;

[0037] It should be clear that the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the embodiments of the present application.

[0038] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of the present application. The singular forms "a," "the," and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0039] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0040] In addition, in the description of this application, unless otherwise specified, "plurality" refers to two or more. "And / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship. The present invention is further described below with reference to the accompanying drawings and examples.

[0041] The present invention is further described below with reference to the accompanying drawings and embodiments.

[0042] Example 1

[0043] Please refer to Figures 1 to 6 This embodiment provides a low-power single-row carrier photodetector, which adopts a GaAsSb / InP material system. The detector comprises, from top to bottom, a P-type contact layer (P contact layer), a block layer (Block layer), an absorber layer (Asober layer), a depleted absorber layer (Depleted Absorber), a cliff layer (Cliff layer), a collector layer (Collector layer), an N-type subcollector layer (Subcollector layer), an N-type contact layer (N contact layer), and a substrate.

[0044] Specifically, the detector has back-incident light input, a cylindrical device shape, a circular table, and a table radius set to 14 μm.

[0045] In a specific embodiment, the material of the P-type contact layer is p-type heavily doped In 0.53 Ga 0.47 As material;

[0046] Specifically, the P-type contact layer has a doping concentration of 2×10 19 cm -3 In 0.53 Ga 0.47 As material to form a good ohmic contact.

[0047] In a specific embodiment, the material of the barrier layer is p-type heavily doped Al 0.3 Ga 0.7 As 0.5 Sb 0.5 Material;

[0048] Specifically, the material of the barrier layer is doped with a concentration of 2×10 19 cm -3 Al 0.3 Ga 0.7 As 0.5 Sb 0.5 Compared to the bandgap width of GaAsSb, this material offers a barrier effect. The heterojunction's energy band transition is gentler, eliminating particularly high electric field spikes, which prevents breakdown and significant restrictions on hole transport. Heavy p-type doping reduces relaxation time, ensuring rapid hole collection without impacting bandwidth.

[0049] In a specific embodiment, the material of the absorption layer is a p-type four-level heavily doped narrow-bandgap GaAsSb material, and the absorption layer includes, from top to bottom, a first absorption layer, a second absorption layer, a third absorption layer, and a fourth absorption layer, and the concentration gradient of the first absorption layer, the second absorption layer, the third absorption layer, and the fourth absorption layer is within a preset range;

[0050] Specifically, the first absorption layer, the second absorption layer, the third absorption layer and the fourth absorption layer form an energy band gradient to enhance the built-in electric field. The concentration gradient is 2×10 18 -4×10 17 cm -3 .

[0051] In a specific embodiment, the depletion absorption layer is made of n-type lightly doped GaAsSb material;

[0052] Specifically, the depletion absorption layer is made of a material with a doping concentration of 1×1016 cm -3 The depletion absorption layer introduces an electric field into the absorption layer to accelerate its electron transport speed, and the overall thickness of the absorption layer and the depletion absorption layer is maintained at 300-500nm.

[0053] In a specific embodiment, the cliff layer is made of n-type heavily doped InP material;

[0054] Specifically, the material of the cliff layer is doped with a concentration of 1.5×10 17 cm -3 The InP material improves the electric field strength at the junction of the absorption layer and the collection layer, thereby increasing the saturation output current.

[0055] In a specific embodiment, the collection layer is made of lightly doped InP material, and the collection layer has an electric field with a preset field strength to reduce junction capacitance and maintain the overshoot speed of electrons in the collection layer;

[0056] Specifically, the collection layer has a thickness of 600 nm and a doping concentration of 1×10 16 cm -3 , the collection layer has an electric field of at least 10 kV / cm.

[0057] In a specific embodiment, the material of the N-type sub-collection layer is n-type heavily doped InP material;

[0058] The thickness of the N-type secondary collection layer is 100 nm, and the doping concentration is 5×10 18 cm -3 The purpose of the N-type sub-collection layer is to reduce the degree of doping concentration mutation between the collection layer and the N-contact layer to avoid excessively high electric field spikes.

[0059] In a specific embodiment, the material of the N-contact layer is n-type heavily doped InP material.

[0060] Specifically, the thickness of the N contact layer is 900 nm, and the doping concentration is 1×10 19 cm -3 The N-contact layer is used to form a good ohmic contact with the N-electrode.

[0061] Compared with existing technologies, the present invention requires lower incident optical power for the same output photocurrent, reducing the energy consumption of EDFAs in optical communication systems. At a wavelength of 1550nm, the imaginary part of the refractive index of GaAsSb is 0.201, and that of InGaAs is 0.09. The PD responsivities of GaAsSb and InGaAs at 300nm are 0.593A / W and 0.329A / W, respectively. The optical powers required to output 80mA of photocurrent are 134.9mW and 243.2mW, respectively.

[0062] Compared to existing technologies, the present invention forms a Type II heterojunction, eliminating the need for a thin (10-30nm) quaternary transition layer to smooth the energy band. Precisely controlling the composition and doping concentration in thinner epitaxial layers is more challenging, which, to a certain extent, reduces the difficulty of epitaxial growth of PDs.

[0063] Example 2

[0064] This embodiment provides a method for preparing a low-power single-row carrier photodetector, comprising the following steps:

[0065] S1: Using metal organic compound chemical vapor deposition technology, an N-type contact layer (N contact layer), an N-type subcollector layer (Subcollector layer), a collector layer (Collector layer), a cliff layer (Cliff layer), a depleted absorber layer (Depleted Absorber layer), an absorber layer (Asober layer), a block layer (Block layer) and a P-type contact layer (P contact layer) are grown in sequence from bottom to top on a semi-insulating substrate to obtain a complete epitaxial wafer;

[0066] S2: Use a maskless UV lithography machine to expose the circular P electrode pattern and alignment marks, and perform surface acid treatment to form a good ohmic contact;

[0067] S3: P electrode is deposited using electron beam evaporation equipment and lift-off is performed using acetone solution;

[0068] S4: Spin-coat HSQ negative resist, overlay the P mesa using an electron beam lithography device, then dry-etch the P mesa using an inductively coupled plasma etching system until the N-type contact layer is reached, and then cleanly etch the HSQ negative resist using a reactive ion beam etching system.

[0069] S5: Expose the N mesa pattern using a maskless UV lithography machine, and etch the InP to the semi-insulating substrate using HCl:H2O=1:1 to form the N mesa, and then remove the resist by bombarding with acetone solution and oxygen plasma;

[0070] S6: Use a maskless UV lithography machine to expose the full electrode pattern and perform surface acid treatment to form a good ohmic contact;

[0071] S7: Full electrode evaporation is performed using an electron beam evaporation device, and lift-off is performed using an acetone solution, and finally rapid thermal annealing is performed to obtain the low-power single-row carrier photodetector.

[0072] Example 3

[0073] This embodiment verifies and analyzes the low-power single-row carrier photodetector preparation method described in Example 1. More specifically:

[0074] Please refer to Figure 5 Although the UTC-PD of the InGaAs / InP material system can improve the responsivity of the InGaAs absorption layer to the same level as GaAsSb by increasing the thickness of the absorption layer, and the device transition bandwidth is basically the same as that of the device of the present invention, the device of the present invention does not require a transition quaternary component and has no requirements for smooth energy band transition, which greatly reduces the difficulty of device epitaxy.

[0075] Please refer to Figure 7 , Figure 7 The carrier transit time limited bandwidth diagram of PD1 and PD2 is 32GHz and 22.2GHz respectively. The thickening of the absorption layer and the collection layer leads to a decrease in the transit bandwidth of PD2, but PD2 has a wider junction depletion region and higher responsivity.

[0076] Please refer to Figure 8 , Figure 8 Figure 2 shows the junction capacitance-cathode bias diagram of PD1 and PD2. Although PD2 has a wider depletion region, its capacitance is still higher than that of PD1 due to the increase in mesa diameter. The purpose of increasing the mesa diameter is to increase the saturated output current. The final comprehensive 3dB bandwidths of PD1 and PD2 are 22.6GHz and 17GHz, respectively.

[0077] Please refer to Figure 9 , Figure 9 Figure 2 shows the saturated output current of PD1 and PD2. The saturated output currents of PD1 and PD2 are 176mA@0.593A / W and 196mA@0.69A / W, respectively.

[0078] Compared to using InGaAs as the absorption layer, the device of the present invention requires lower incident optical power for the same output photocurrent, which can reduce the energy consumption of EDFAs in optical communication systems. At a wavelength of 1550nm, the imaginary part of the refractive index of GaAsSb is 0.201, while that of InGaAs is 0.09. Simulations show that the PD responsivities corresponding to 300nm GaAsSb and InGaAs are 0.593A / W and 0.329A / W, respectively, and the optical powers required to output 80mA of photocurrent are 134.9mW and 243.2mW, respectively.

[0079] The present invention forms a type II heterojunction in a GaAsSb / InP system, eliminating the need for a thin (10-30nm) quaternary transition layer to smooth the energy band. Precisely controlling the composition and doping concentration in thin epitaxial layers is challenging, which reduces the difficulty of epitaxial growth of PDs to a certain extent.

[0080] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A low-power single-row carrier photodetector, characterized in that: The detector adopts a GaAsSb / InP material system, and the detector comprises a P-type contact layer, a barrier layer, an absorption layer, a depletion absorption layer, a cliff layer, a collection layer, an N-type sub-collection layer, an N-type contact layer, and a substrate from top to bottom. The material of the P-type contact layer is p-type heavily doped In 0.53 Ga 0.47 As material; The material of the barrier layer is p-type heavily doped Al 0.3 Ga 0.7 As 0.5 Sb 0.5 Material; The absorption layer is made of p-type four-level heavily doped narrow-bandgap GaAsSb material, and the absorption layer includes, from top to bottom, a first absorption layer, a second absorption layer, a third absorption layer, and a fourth absorption layer, wherein the concentration gradient of the first absorption layer, the second absorption layer, the third absorption layer, and the fourth absorption layer is within a preset range; The first absorption layer, the second absorption layer, the third absorption layer and the fourth absorption layer form an energy band gradient to enhance the built-in electric field. The concentration gradient is 2×10 18 -4×10 17 cm -3 ; The depletion absorption layer is made of n-type lightly doped GaAsSb material; The material of the cliff layer is n-type heavily doped InP material; The collection layer is made of lightly doped InP material, and the collection layer has an electric field with a preset field strength to reduce the junction capacitance and maintain the overshoot speed of electrons in the collection layer; The material of the N-type sub-collection layer is n-type heavily doped InP material; The material of the N-type contact layer is heavily n-type doped InP material.

2. A method for preparing a low-power single-row carrier photodetector is applied to the low-power single-row carrier photodetector according to claim 1, characterized in that: The following steps are involved: S1: Using metal organic compound chemical vapor deposition technology, an N-type contact layer, an N-type sub-collection layer, a collection layer, a cliff layer, a depletion absorption layer, an absorption layer, a barrier layer, and a P-type contact layer are grown in sequence from bottom to top on a semi-insulating substrate to obtain a complete epitaxial wafer; S2: Use a maskless UV lithography machine to expose the circular P electrode pattern and alignment marks, and perform surface acid treatment to form a good ohmic contact; S3: P electrode is deposited using electron beam evaporation equipment and lift-off is performed using acetone solution; S4: Spin-coat HSQ negative resist, overlay the P mesa using an electron beam lithography device, then dry-etch the P mesa using an inductively coupled plasma etching system until the N-type contact layer is reached, and then cleanly etch the HSQ negative resist using a reactive ion beam etching system. S5: Expose the N mesa pattern using a maskless UV lithography machine, and etch the InP to the semi-insulating substrate using HCl:H2O=1:1 to form the N mesa, and then remove the resist by bombarding with acetone solution and oxygen plasma; S6: Use a maskless UV lithography machine to expose the full electrode pattern and perform surface acid treatment to form a good ohmic contact; S7: Full electrode evaporation is performed using an electron beam evaporation device, and lift-off is performed using an acetone solution, and finally rapid thermal annealing is performed to obtain the low-power single-row carrier photodetector.

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