III-nitride dual-resolution detector, imaging array and imaging method

Abstract

The invention discloses a group III nitride two-color resolution detector, an imaging array and an imaging method. The detector comprises a substrate layer, a wide forbidden band layer, a narrow forbidden band layer, an electrode cathode and an electrode anode. The array comprises a plurality of III-nitride two-color resolution detectors which are arranged in parallel. The method comprises the steps that an optical signal enters from the top of the detector, a long wavelength component in the incident light is absorbed in a narrow forbidden band layer, a short wavelength component is sequentially absorbed in the narrow forbidden band layer and a wide forbidden band layer, and the detector works under zero bias voltage or negative bias voltage to generate a negative current signal to be output; the detector works under the positive bias voltage to generate positive current output; and collecting output current signals to obtain imaging results of two different wavelengths. According to the invention, the wavelength selection detection effect and the two-color resolution detection imaging effect can be realized by a single device without filtering. The III-nitride two-color resolution detector, the imaging array and the imaging method can be widely applied to the technical field of photoelectric detection imaging.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection and imaging technology, and in particular to a group III nitride dual-color resolution detector, an imaging array, and an imaging method. Background Art

[0002] As a key component of the electromagnetic spectrum, the ultraviolet-visible light band has extensive and critical detection and imaging applications in numerous fields, including industrial and agricultural production, social life, national defense and military industry, and scientific research experiments. Generally speaking, the intensity and wavelength of the incident light signal are core information. Achieving high-sensitivity and high-speed detection of light intensity, as well as convenient wavelength resolution, has become a common and highly anticipated challenge in the ultraviolet-visible light application field. For example, wireless communications, posture detection, and gesture recognition applications using visible light, flame and high-voltage corona detection and imaging using ultraviolet light, as well as color imaging, biosignal recognition, and multispectral detection and imaging, all place stringent demands on the detection end, requiring both high sensitivity and high speed to quickly detect weak signals, as well as wavelength selection and resolution capabilities to avoid interference from other bands.

[0003] In traditional detection and imaging, a filtering-then-detection approach is commonly used to achieve color resolution and intensity recognition. For example, current CMOS imaging chip systems widely utilize the Bayer filter pattern, requiring four detector units paired with four RGGB color filters to form a single pixel, thereby achieving color imaging. However, this filtering-then-detection approach has significant drawbacks. It not only significantly increases system cost and size, but also reduces the detector's quantum efficiency due to the use of filters, resulting in poor detection performance. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a III-nitride dual-color resolution detector, imaging array and imaging method, which can distinguish and identify under different bias voltages, so as to achieve the effect of wavelength selective detection without filtering in a single device and the dual-color resolution detection / imaging effect.

[0005] The first technical solution adopted by the present invention is: a group III nitride dual-color resolution detector, comprising a substrate layer, a wide bandgap layer, a narrow bandgap layer, an electrode cathode and an electrode anode, wherein the material of the detector is group III nitride, the wide bandgap layer covers the upper surface of the substrate layer, the narrow bandgap layer is provided on one upper surface of the wide bandgap layer, the electrode cathode is provided on the other upper surface of the wide bandgap layer, and the electrode anode is provided on the upper surface of the narrow bandgap layer, wherein:

[0006] The substrate layer is used to support the detector structure;

[0007] The wide bandgap layer is used to absorb the short wavelength component of the incident light;

[0008] The narrow bandgap layer is used to absorb the long wavelength component and the short wavelength component of the incident light;

[0009] The electrode cathode and the electrode anode are used to provide an operating voltage and realize carrier collection.

[0010] Furthermore, the substrate layer supports the growth of the metal atomic plane of the detector structure perpendicular to the (0001) crystal plane, and forms polarized negative charges at the interface between the wide bandgap layer and the narrow bandgap layer.

[0011] Furthermore, the wide bandgap layer specifically includes a first n-type contact layer and a first unintentionally doped barrier layer, the first unintentionally doped barrier layer is located above the first n-type contact layer, and the electrode cathode is arranged on the upper surface of the first n-type contact layer.

[0012] Furthermore, the narrow bandgap layer specifically includes a second n-type contact layer and a second unintentionally doped barrier layer, the second n-type contact layer is located above the second unintentionally doped barrier layer, the electrode anode is arranged on the upper surface of the second n-type contact layer, and the thickness of the narrow bandgap layer does not exceed 250nm.

[0013] Furthermore, the lattice constant in the wide bandgap layer is smaller than the lattice constant in the narrow bandgap layer, forming a bidirectional polarization electric field, and the electron concentrations in the wide bandgap layer and the narrow bandgap layer do not exceed 5×10 18 cm -3 .

[0014] Furthermore, the electrode cathode and the electrode anode form ohmic contacts with the wide bandgap layer and the narrow bandgap layer respectively, and the contact barriers of the ohmic contacts are lower than 0.5 eV.

[0015] Furthermore, the external electric field current when the detector is working includes a negative bias or zero bias current and a positive bias current, wherein the negative bias or zero bias current corresponds to the short wavelength component in the incident signal, and the positive bias current corresponds to the sum of the short wavelength and long wavelength components.

[0016] The second technical solution adopted by the present invention is: an imaging array of a III-nitride dual-color resolution detector, comprising a plurality of III-nitride dual-color resolution detectors arranged in parallel.

[0017] The third technical solution adopted by the present invention is: an imaging method of an imaging array of a group III nitride dual-color resolution detector, comprising the following steps:

[0018] The detector operates under zero bias or negative bias, enhancing the built-in electric field on one side of the wide bandgap layer. The short-wavelength absorption in the incident signal forms photogenerated carriers that drift to the electrode cathode set on the wide bandgap layer, generating a negative current signal output.

[0019] When the detector works under positive bias, the electric field of the narrow bandgap layer is enhanced in the same direction as the external electric field, the electric field of the wide bandgap layer is weakened, the potential barrier is lowered, and electrons diffuse from the wide bandgap layer into the narrow bandgap layer and are collected by the electrode anode, generating a positive current output;

[0020] The negative current signal output and the positive current output are collected to obtain imaging results of two different wavelengths.

[0021] The beneficial effects of the method and system of the present invention are as follows: the present invention utilizes the absorption of two different bandgap width materials in the III-nitride heterojunction to cause two different current mechanisms, namely electron diffusion and electron drift, inside the device, thereby performing discrimination and identification under different bias voltages, so as to achieve the effect that a single device can perform wavelength selective detection without filtering. The response under the two bias voltages is combined to decouple the intensity distribution of the two wavelength components in the incident light signal, that is, the dual-color resolution detection / imaging effect. The detector imaging array composed of the dual-color resolution detector can break through the traditional Bayer filter mode, eliminate the need for additional filtering structure and effectively reduce the number of devices required for a single pixel element, greatly reducing the detection cost and the size of the detection system while achieving high-efficiency detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a Group III nitride dual-color resolution detector according to the present invention;

[0023] Figure 2 This is a schematic diagram of the steps of an imaging method for a group III nitride dual-color resolution detector array according to the present invention;

[0024] Figure 3 This is a schematic diagram provided in a specific embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram provided in the third specific embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram provided by a fourth specific embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of IV test results provided in the fifth specific embodiment of the present invention.

[0028] Reference numerals: 101, substrate layer; 102, wide bandgap layer; 103, narrow bandgap layer; 104, cathode electrode; 105, anode electrode. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are provided for ease of description only and do not limit the order of the steps. The order of execution of the steps in the embodiments can be adaptively adjusted based on the understanding of those skilled in the art.

[0030] First, it should be noted that the embodiments of the present invention innovatively propose an ultraviolet-visible light detector and its imaging array with built-in wavelength resolution capability, which can significantly reduce costs and simplify the detection system architecture. It is of extremely critical and far-reaching significance for promoting the performance improvement of various applications and the development towards portability and intelligence.

[0031] Reference Figure 1 The present invention provides a group III nitride dual-color resolution detector, comprising a substrate layer 101, a wide bandgap layer 102, a narrow bandgap layer 103, an electrode cathode 104, and an electrode anode 105. The material of the detector is group III nitride, the wide bandgap layer covers the upper surface of the substrate layer, the narrow bandgap layer is provided on one upper surface of the wide bandgap layer, the electrode cathode is provided on the other upper surface of the wide bandgap layer, and the electrode anode is provided on the upper surface of the narrow bandgap layer, wherein:

[0032] The substrate layer is used to support the detector structure;

[0033] Specifically, the substrate layer supports the growth of the metal atomic plane of the detector structure perpendicular to the (0001) crystal plane, and forms polarized negative charges at the interface between the wide bandgap layer and the narrow bandgap layer.

[0034] In this embodiment, the substrate layer of the detector is a material that supports the device structure grown along the

[0001] crystal direction, including sapphire, Si, AlN, GaN, etc. When the device is working, the light signal is incident from the top (the other side of the substrate).

[0035] In some specific embodiments, the substrate material acts as an epitaxial template for the device or provides physical support. The materials include but are not limited to sapphire, Si, GaN, AlN, quartz, ZnO, Ga2O3, or other materials that can serve as a Group III nitride substrate. The substrate material needs to support the growth of the device along the

[0001] crystal direction, that is, the metal atomic plane perpendicular to the (0001) crystal plane, thereby having a lower surface state density and higher epitaxial crystal quality; in addition, crystal growth along the

[0001] crystal direction can form polarized negative charges at the narrow bandgap / wide bandgap interface, meeting the needs of electric field construction.

[0036] The wide bandgap layer is used to absorb the short wavelength component of the incident light;

[0037] Specifically, the wide bandgap layer includes a first n-type contact layer and a first unintentionally doped barrier layer. The first unintentionally doped barrier layer is located above the first n-type contact layer. The electrode cathode is provided on the upper surface of the first n-type contact layer.

[0038] The narrow bandgap layer is used to absorb the long wavelength component and the short wavelength component of the incident light;

[0039] Specifically, the narrow bandgap layer includes a second n-type contact layer and a second unintentionally doped barrier layer. The second n-type contact layer is located above the second unintentionally doped barrier layer. The electrode anode is arranged on the upper surface of the second n-type contact layer. The thickness of the narrow bandgap layer does not exceed 250nm to prevent the short wavelength component in the incident signal from being unable to transmit to the wide bandgap layer below.

[0040] In some embodiments, the thickness of the narrow bandgap layer of the detector does not exceed 250 nm, thereby allowing short wavelength components to transmit to the underlying wide bandgap layer.

[0041] More specifically, the lattice constant in the wide bandgap layer is smaller than the lattice constant in the narrow bandgap layer, forming a bidirectional polarization electric field, and the electron concentrations in the wide bandgap layer and the narrow bandgap layer do not exceed 5×10 18 cm -3 .

[0042] In some specific embodiments, the lattice constant in the wide bandgap layer of the detector is smaller than the lattice constant in the narrow bandgap layer, thereby forming a bidirectional polarization electric field directed from both sides to the interface between the two layers.

[0043] More specifically, the wide bandgap layer and the narrow bandgap layer are both group III nitride materials, including AlN, GaN, InN and alloys formed by these three. The orientation of the wide bandgap and narrow bandgap group III nitride material layers on the substrate material is also (0001) crystal plane orientation (c-plane orientation); the in-plane lattice constant of the wide bandgap layer is smaller than the in-plane lattice constant of the narrow bandgap layer, thereby forming a heterojunction; the wide bandgap layer and the narrow bandgap layer can be AlN and AlGaN, or Al x GaN and Al y GaN(x>y), or AlGaN and GaN, or GaN and InGaN, or In y GaN and In x GaN (x>y), or AlGaN and InGaN, or AlN and GaN; the conductivity type of the wide bandgap layer and the narrow bandgap layer is intrinsic or n-type conductivity, including but not limited to unintentionally doped nitride materials and Si-doped nitride materials; if the wide bandgap layer and the narrow bandgap layer are n-type doped materials, the electron concentration should not be higher than 5×10 18 cm -3Otherwise, the depletion width of the polarization electric field in these two layers of materials will be too narrow, and the detection efficiency of the device will be seriously degraded.

[0044] The electrode cathode and the electrode anode are used to provide an operating voltage and realize carrier collection.

[0045] Specifically, the cathode electrode and the anode electrode form ohmic contacts with the wide bandgap layer and the narrow bandgap layer respectively, and the contact potential barriers of the ohmic contacts are lower than 0.5 eV.

[0046] In some specific embodiments, the cathode and anode electrodes of the detector are respectively made on the wide bandgap layer and the narrow bandgap layer. The electrode materials used include but are not limited to Ti / Au, In, V / Au, Ti / Al / Ni / Au, etc. The cathode and anode materials used are preferably able to form low-resistance ohmic contacts with semiconductor materials. If there is no suitable ohmic contact electrode process, it is better to form a contact barrier as low as possible to avoid hindering the carrier collection process.

[0047] Furthermore, the external electric field current of the detector during operation includes a negative bias or zero bias current and a positive bias current, wherein the negative bias or zero bias current corresponds to the short wavelength component in the incident signal, and the positive bias current corresponds to the sum of the short wavelength and long wavelength components.

[0048] An imaging array of a III-nitride dual-color resolution detector comprises a plurality of parallel-arranged III-nitride dual-color resolution detectors.

[0049] In this embodiment, the imaging array is composed of n rows and m columns of detectors arranged on the same substrate, where n, m ≥ 2; during imaging, the light signal is directly incident on the array from above the array (away from the substrate side) without passing through a filtering / spectroscopy structure, and the two bands are imaged separately by driving the device array through negative / zero bias and positive bias. When the device is working, it is necessary to measure the current under the two biases, where the negative bias or zero bias current corresponds to the short wavelength component in the incident signal, and the positive bias current corresponds to the sum of the short wavelength and long wavelength components.

[0050] Reference Figure 2 , an imaging method for an imaging array of a group III nitride dual-color resolution detector, comprising the following steps:

[0051] S100, the light signal is incident from the top of the detector. The long wavelength component of the incident light is absorbed in the narrow bandgap layer, and the short wavelength component is absorbed in the narrow bandgap layer and the wide bandgap layer in sequence.

[0052] Specifically, when the detector is working, the light signal is incident from the top of the device (the other side of the substrate). The signal light can be monochromatic light or mixed color light. The signal will pass through the narrow bandgap layer and the wide bandgap layer layer by layer, where the long wavelength component is only absorbed in the narrow bandgap layer, while the short wavelength signal will be absorbed by the narrow bandgap layer and the wide bandgap layer in turn.

[0053] S200, the detector operates under zero bias or negative bias, enhancing the built-in electric field on one side of the wide bandgap layer, and the photogenerated carriers formed by the short-wavelength absorption in the incident light signal drift to the electrode cathode set on the wide bandgap layer, generating a negative current signal output;

[0054] Specifically, when the device is under zero bias or negative bias, the built-in electric field on one side of the wide bandgap layer will be enhanced, and the photogenerated carriers formed by the short-wavelength absorption will drift to the electrode cathode set on the wide bandgap layer, generating a negative current signal output. The intensity of the negative current is positively correlated with the intensity of the short-wavelength component in the incident signal.

[0055] S300, the detector works under positive bias. The electric field of the narrow bandgap layer is enhanced in the same direction as the external electric field, while the electric field of the wide bandgap layer is weakened and the potential barrier is lowered. Electrons diffuse from the wide bandgap layer into the narrow bandgap layer and are collected by the electrode anode, generating a positive current output.

[0056] Specifically, under a sufficient positive bias voltage, the electric field of the narrow bandgap layer is enhanced in the same direction as the external electric field, and the electric field of the wide bandgap layer is weakened, and the barrier is lowered. Electrons can easily diffuse from the wide bandgap material into the narrow bandgap layer and be collected by the anode to form a positive current. At this time, the holes generated by light absorption in the two layers will drift to the heterojunction interface, causing the potential barrier to be lowered and contributing to the electron diffusion injection current. Therefore, the output current signal intensity is the superposition of the two wavelength components in the incident signal.

[0057] S400: Collect the negative current signal output and the positive current output to obtain imaging results of two different wavelengths.

[0058] Specifically, incident signals with more than one wavelength component are incident from above the detector array, that is, from the side away from the substrate. The array is driven to collect signals under negative / zero bias and positive bias, respectively, thereby obtaining imaging results of two different wavelengths.

[0059] Therefore, it is only necessary to test the output current of a single device under a specific negative bias and a characteristic positive bias to invert the intensity of the two wavelength components in the incident signal, and achieve the effect of single device non-filtering color mixing and dual-color resolution detection. The wavelength range that needs to be resolved can be designed by setting the materials of the wide bandgap layer and the narrow bandgap layer. For example, the narrow bandgap layer / wide bandgap layer uses Al 0.23 GaN / Al 0.4 GaN heterojunction can realize the detection of UVB and UVC bands; In0.07 GaN / Al 0.23 GaN heterojunction can achieve UVA and shorter wavelength resolution detection; using In 0.15 GaN / In 0.07 GaN heterojunctions can achieve differentiated detection in both blue and ultraviolet wavelengths. An imaging array composed of Group III nitride dual-color resolution detectors, where the basic pixel unit uses the dual-color resolution detector of the present invention, can achieve single-pixel dual-color imaging without the need for additional filters.

[0060] Further description will be made with reference to the accompanying drawings of the embodiments of this solution: Specific embodiment one:

[0062] like Figure 3 As shown, an AlGaN-based UVC / UVB dual-color resolution detector mainly includes a substrate layer, a wide bandgap layer, a narrow bandgap layer, an electrode anode and an electrode cathode arranged in sequence from bottom to top.

[0063] The substrate layer is made of a c-plane AlN epitaxial template; the wide bandgap layer is AlGaN material with 40% Al content grown on AlN, with a weak n-type doping and an electron concentration of 5×10 17 cm -3 , with a thickness of 200nm; the narrow bandgap layer is AlGaN material with an Al component of 23%, the doping type is weak n-type doping, and the electron concentration is 5×10 17 cm -3 , with a thickness of 120nm; the electrode cathode and electrode anode are both Ti / Al / Ni / Au, with thicknesses of 15 / 80 / 20 / 60nm.

[0064] In this embodiment, the c-plane oriented Al 0.23 GaN / Al 0.4 The GaN interface will generate negative polarization surface charge due to the polarization effect, causing the nearby semiconductor to be depleted and forming a bidirectional electric field pointing to the interface. Under negative bias, the wide bandgap layer Al 0.4 The UVC band absorption in GaN forms an electron drift current, and the electrons flow to the cathode to form a negative current. At this time, the electric field of the narrow bandgap layer is weakened, and the UVB absorption hardly contributes to the response. Under positive bias, the holes contributed by the UVC absorption in the wide bandgap layer and the UVB absorption in the narrow bandgap will flow to the interface and accumulate, causing the barrier to be lowered and the electrons to be diffusely injected (from the wide bandgap layer to the narrow bandgap layer), forming a positive current. At this time, the current response is contributed by both the UVB and UVC components in the incident signal. Therefore, by testing the -2V current and the +2V current, the respective intensities of the UVB and UVC components in the mixed-color incident signal can be measured through a single device. Specific embodiment two:

[0066] The difference between this embodiment and the first embodiment is that the wide bandgap layer and the narrow bandgap layer used are Al 0.23 GaN and In 0.07 GaN can achieve single-device filter-free measurement of the UVB and UVA wavelength components in the mixed color signal. Specific embodiment three:

[0068] The device structure of this embodiment is as follows Figure 4 As shown, the difference from Example 1 is that in this embodiment, the wide bandgap layer is subdivided into an unintentional doping layer and a heavily doped contact layer, and the narrow bandgap layer is subdivided into an unintentional doping layer and a heavily doped contact layer. The heterojunction interface, that is, by subdividing the doping distribution of these two layers, the electron concentration at the heterojunction interface is low, thereby forming a higher built-in polarization electric field, thereby promoting the separation and transport of carriers and improving the quantum efficiency of the device. At the same time, the material under the electrode is heavily doped n-type, which can provide more diffuse electrons, while reducing the contact resistance and improving the positive bias current response. The prepared detector will be able to achieve more efficient UVC and UVB dual-color resolution detection. Specific embodiment four:

[0070] The device structure of this embodiment is as follows Figure 5 As shown, the substrate material used is c-plane sapphire, the wide bandgap layer and narrow bandgap layer used are unintentionally doped (uid-)GaN and uid-InGaN respectively, and the cathode and anode electrodes used are both Ti / Au. This embodiment device can achieve filter-free dual-color detection of blue-violet light and ultraviolet light. Specific embodiment five:

[0072] This example is the IV test result of the detector in Example 4. Figure 6 As shown in the figure: Under 0V bias, the detector's response current to the UV LED is as high as 19nA, while the response current to the visible light LED with similar irradiation intensity is only 2.1pA, a difference of about four orders of magnitude, indicating that the device only responds to UV light under 0 bias; under +1V bias, the device has a relatively high current response to both wavelengths. Therefore, combining the current responses under these two biases can obtain the intensities of UV and visible light in the incident signal.

[0073] In summary, the dual-color resolution detector of the present invention comprises, arranged sequentially from bottom to top, a substrate material, a wide bandgap layer, a narrow bandgap layer, and a cathode and anode electrodes disposed thereon. The substrate material provides base support for device growth and fabrication, maintaining epitaxial structure growth along the

[0001] crystal orientation. The wide bandgap layer is a Group III nitride material with a smaller lattice constant, while the narrow bandgap layer has a larger lattice constant. Therefore, a bidirectional polarization electric field is formed in these two layers, with both sides pointing toward the interface. The cathode and anode preferably form ohmic contact or low contact resistance with the semiconductor layer they contact. The imaging array consists of multiple devices arranged on the same substrate. When the device or array is operating, a light signal is incident from the top. The long-wavelength component of the incident light is absorbed only in the narrow bandgap layer, while the short-wavelength component is absorbed in the narrow bandgap layer and then in the wide bandgap layer. Under zero bias and negative bias, the electric field in the wide bandgap layer is stronger, and the short-wavelength light absorption therein forms a drift current that dominates, that is, the device only responds to the short-wavelength component. Under positive bias, the electric field in the narrow bandgap layer is enhanced, while the electric field in the drift layer is weakened. The long-wavelength light absorption in the narrow bandgap layer and the short-wavelength absorption in the wide bandgap layer jointly induce a diffusion current that dominates. At this time, the device response is derived from the sum of the two wavelength components. Therefore, the response under the two biases can be combined to decouple the intensity distribution of the two wavelength components in the incident light signal, that is, the dual-color resolution detection / imaging effect. Based on the dual-color resolution detector, the detector imaging array can break through the traditional Bayer filter mode, eliminating the need for additional filtering structures and effectively reducing the number of devices required for a single pixel element. While achieving high-efficiency detection, it greatly reduces the detection cost and reduces the size of the detection system.

[0074] Therefore, the embodiments of the present invention have the following advantages compared with the prior art:

[0075] 1) Utilizing the absorption of two materials with different bandgap widths within the III-nitride heterojunction, the device induces two different current mechanisms: electron diffusion and electron drift. This allows for discrimination and identification under different bias voltages, achieving the effect of wavelength-selective detection in a single device without filtering. This can further enable the development of single-pixel multi-color resolution imaging arrays and imaging methods. Compared to the most mature and commonly used Si-based detectors in the UV-visible light band, the III-nitride detector of the present invention can directly detect short-wavelength components using wide-bandgap materials without filters, thereby achieving a detector structure with higher sensitivity, lower cost, and a simpler, smaller, and easier-to-integrate structure. In particular, for applications requiring wavelength-resolved detection or imaging, the dual-color resolution detector of the present invention can significantly reduce the number of detectors required and the space required for the detection system. This means that a single device / pixel can achieve the effect of combining multiple devices and filtering systems in traditional technologies. This allows for cost-effective applications in a variety of emerging applications, such as wearables and mobile terminals, while reducing costs and increasing efficiency. This has important and practical significance for the miniaturization, low cost, portability, and intelligent development of color-resolved detection systems.

[0076] 2) Utilizing the polarization effect of the III-nitride heterojunction itself to construct the built-in electric field of the semiconductor device can, on the one hand, avoid the difficulties and disadvantages of p-type doping of wide-bandgap materials, and achieve sensitivity and speed performance that is superior to traditional nitride material pn junction architecture detectors. On the other hand, it can greatly simplify the detector epitaxial structure and improve the quality of the epitaxial crystal, thereby greatly reducing the difficulty of material growth and device fabrication while achieving better device uniformity and higher yield.

[0077] 3) The use of simple and effective polarization heterostructures can also provide basic support for further integration of multiple heterojunctions to achieve single-device resolution detection and imaging of more wavelengths / colors.

[0078] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A III-nitride dual-color resolution detector, characterized in that: The detector comprises a substrate layer, a wide bandgap layer, a narrow bandgap layer, an electrode cathode and an electrode anode. The material of the detector is group III nitride. The wide bandgap layer covers the upper surface of the substrate layer. The narrow bandgap layer is provided on one upper surface of the wide bandgap layer, the electrode cathode is provided on the other upper surface of the wide bandgap layer, and the electrode anode is provided on the upper surface of the narrow bandgap layer, wherein: The substrate layer is used to support the detector structure; The wide bandgap layer is used to absorb the short wavelength component of the incident light; The narrow bandgap layer is used to absorb the long wavelength component and the short wavelength component of the incident light; The electrode cathode and the electrode anode are used to provide an operating voltage and realize carrier collection.

2. The III-nitride dual-color resolution detector according to claim 1, characterized in that: The substrate layer supports the growth of the metal atomic plane of the detector structure perpendicular to the (0001) crystal plane, and forms polarized negative charges at the interface between the wide bandgap layer and the narrow bandgap layer.

3. The III-nitride dual-color resolution detector according to claim 2, characterized in that: The wide bandgap layer specifically includes a first n-type contact layer and a first unintentionally doped barrier layer. The first unintentionally doped barrier layer is located above the first n-type contact layer. The electrode cathode is disposed on the upper surface of the first n-type contact layer.

4. The III-nitride dual-color resolution detector according to claim 3, characterized in that: The narrow bandgap layer specifically includes a second n-type contact layer and a second unintentionally doped barrier layer. The second n-type contact layer is located above the second unintentionally doped barrier layer. The electrode anode is arranged on the upper surface of the second n-type contact layer. The thickness of the narrow bandgap layer does not exceed 250nm.

5. The III-nitride dual-color resolution detector according to claim 4, characterized in that: The lattice constant in the wide bandgap layer is smaller than that in the narrow bandgap layer, forming a bidirectional polarization electric field, and the electron concentration in the wide bandgap layer and the narrow bandgap layer does not exceed 5×10 18 cm -3 .

6. The III-nitride dual-color resolution detector according to claim 5, characterized in that: The cathode electrode and the anode electrode form ohmic contacts with the wide bandgap layer and the narrow bandgap layer respectively, and the contact potential barriers of the ohmic contacts are lower than 0.5 eV.

7. The III-nitride dual-color resolution detector according to claim 6, characterized in that: The external electric field current of the detector when working includes negative bias or zero bias current and positive bias current, wherein the negative bias or zero bias current corresponds to the short wavelength component in the incident signal, and the positive bias current corresponds to the sum of the short wavelength and long wavelength components.

8. An imaging array of a III-nitride dual-color resolution detector, characterized in that: The invention comprises a plurality of group III nitride dual-color resolution detectors as claimed in claim 1 arranged in parallel.

9. An imaging method for an imaging array of a group III nitride dual-color resolution detector, comprising the following steps: The optical signal is incident from the top of the detector. The long wavelength component of the incident light is absorbed in the narrow bandgap layer, and the short wavelength component is absorbed in the narrow bandgap layer and the wide bandgap layer in turn. The detector operates under zero bias or negative bias, enhancing the built-in electric field on one side of the wide bandgap layer. The short-wavelength absorption in the incident light signal generates photogenerated carriers that drift to the electrode cathode set on the wide bandgap layer, generating a negative current signal output. When the detector works under positive bias, the electric field of the narrow bandgap layer is enhanced in the same direction as the external electric field, the electric field of the wide bandgap layer is weakened, the potential barrier is lowered, and electrons diffuse from the wide bandgap layer into the narrow bandgap layer and are collected by the electrode anode, generating a positive current output; The negative current signal output and the positive current output are collected to obtain imaging results of two different wavelengths.

Images