Optical detector of nanometer spherical body structure quantum dots

Abstract

The optical detector comprises a GaAs substrate, an N-type doping layer, a quantum dot layer and a P-type doping layer are epitaxially grown on the GaAs substrate layer by layer, an ITO thin film layer is arranged on the surface of the P-type doping layer, a metal bottom electrode thin film layer is arranged below the GaAs substrate, and the quantum dot layer is of an orderly-arranged nanometer spherical structure. The nanosphere structure can achieve the beneficial effects of enhancing light absorption, reducing light reflection loss and improving detection sensitivity and speed, and the quantum dot layer is introduced into the nanosphere structure, so that the beneficial effects of uniform electric field distribution, enhanced optical coupling efficiency, better light capturing capability, uniform heat distribution and optimized light transmission path can be achieved. Therefore, the performance of the optical detector is effectively improved.

Description

Technical Field

[0001] The utility model relates to the field of integrated photon devices, in particular to a gallium arsenide photodetector with a micro-nano structure. Background Technique

[0002] A photodetector is a device that converts optical signals into electrical signals and is widely used in fields such as communication, imaging, sensing, and measurement. Traditional photodetectors mostly use silicon materials. However, due to the relatively wide bandgap of silicon materials, the absorption efficiency of infrared light is relatively low. Therefore, alternative materials need to be found in many applications; gallium arsenide (GaAs) is a semiconductor material with a direct bandgap and has excellent optoelectronic properties, including high electron mobility, high light absorption coefficient, and small bandgap width. Especially in the near-infrared and infrared bands, gallium arsenide materials exhibit excellent light absorption ability, making it an ideal choice for high-performance photodetectors; micro-nano structures have broad application prospects, especially in applications with high sensitivity, wide band, and high-resolution requirements, such as biomedical imaging, environmental monitoring, space exploration, and high-speed optical communication. Combining micro-nano structures is also the development direction of photodetectors. Content of the Utility Model

[0003] The purpose of the utility model is to provide a photodetector with a quantum dot of a nano-spherical structure on a gallium arsenide substrate, aiming to solve the problem of further improving the performance of the photodetector.

[0004] The technical solution adopted by the utility model is: a photodetector with a quantum dot of a nano-spherical structure, including a GaAs substrate. An N-type doped layer, a quantum dot layer, and a P-type doped layer are epitaxially grown layer by layer on the GaAs substrate. There is an ITO thin film layer on the surface of the P-type doped layer, and there is a metal bottom electrode thin film layer under the GaAs substrate. The quantum dot layer is an ordered nano-spherical structure.

[0005] A further technical solution of the utility model is: the nano-spherical structure is obtained by processing the quantum dot layer through nano-sphere lithography technology and etching technology.

[0006] The beneficial effects of the utility model are: due to the adoption of the above technical solution, the nano-spherical structure of the photodetector with a quantum dot of a nano-spherical structure of the utility model can obtain beneficial effects of enhanced light absorption, reduced light reflection loss, improved detection sensitivity and speed. Introducing a quantum dot layer into the nano-spherical structure can obtain beneficial effects of uniform electric field distribution, enhanced light coupling efficiency, better light trapping ability, uniform heat distribution, and optimized light transmission path. All of the above effectively improve the performance of the photodetector. Description of the Drawings

[0007] Figure 1It is a schematic structural diagram of a photodetector with a quantum dot of a nano-spherical structure according to the present utility model. Specific embodiments

[0008] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0009] Example:

[0010] As Figure 1 shown, a photodetector with a quantum dot of a nano-spherical structure is processed with micro-nano structures on a gallium arsenide product with epitaxially grown quantum dots. The structure from bottom to top is a metal bottom electrode thin film layer (negative electrode) 1, a GaAs (gallium arsenide) substrate 2, an N-type doped layer 3, a quantum dot layer 4, a P-type (doped layer 5, an ITO (indium tin oxide) thin film layer (positive electrode) 6.

[0011] The N-type doped layer contains a dopant, and the dopant is an element that supplies electrons, such as Si (silicon) with a doping concentration of 10 17 ~ 10 19 atoms / cm³.

[0012] The P-type doped layer contains a dopant, and the dopant is an element that accepts electrons, such as Be (beryllium), with a doping concentration of 10 17 ~ 10 19 atoms / cm³.

[0013] The formation principle of the shape structure is to epitaxially grow an N-type doped layer and a quantum dot layer layer by layer directly on the GaAs substrate, and then obtain a nano-spherical structure through nano-sphere lithography technology and etching technology. At this time, the structure contains quantum dots; then a P-type doped layer is continuously grown epitaxially on the above structure; finally, an ITO thin film is sputtered onto the surface, and a metal electrode is sputtered and plated after thinning and polishing on the back.

[0014] The nano-spherical structure can enhance the performance of photodetectors: The nano-spherical structure can increase the light absorption efficiency through multiple mechanisms. First, this structure can increase the path length of incident light on the detector surface, enabling light to have more opportunities to be absorbed rather than simply reflected or transmitted. Second, the shape of the nano-spherical structure can cause light diffraction and scattering, thereby increasing the distribution uniformity and residence time of light in the active layer. The nano-spherical structure can effectively reduce the reflection of light at the interface, increasing light transmission and absorption. This is because these structures provide a gradually varying refractive index gradient from air to the interior of the material. The nano-sphere structure itself is a tiny gradient refractive index lens, which can cause the bending of the light wave path when the light wave passes through the nano-sphere. When light enters from one medium into another medium with a different refractive index, the light will refract. At the edge of the nano-sphere, the refractive index difference between the different materials encountered by the light is relatively large, while in the central part, this difference gradually decreases. This helps to overcome the reflection problem caused by the sudden refractive index change at the traditional planar interface. Due to the enhanced light absorption and reduced reflection, the nano-spherical structure can significantly improve the detection sensitivity. The increased light absorption means that more photons are converted into electron-hole pairs, thus increasing the generated photocurrent, which is particularly important for detection in low-light environments. In addition, this structure reduces the movement path of carriers in the material, so it helps to quickly transport photo-generated carriers, thereby improving the response speed.

[0015] The confinement of the nano-spherical structure on quantum dots also plays a certain role in the performance of quantum dots and photodetectors. The spherical structure can provide a more uniform electric field distribution, which helps quantum dots work better throughout the structure. This uniform electric field can improve the photoelectric conversion efficiency of quantum dots and enhance the overall performance of photodetectors. The spherical structure can effectively focus incident light, making it easier for quantum dots to absorb light. The multiple reflections and scattering of light within the sphere can increase the light path length and improve the light absorption efficiency.

[0016] The spherical structure helps to capture incident light from all directions, improving the light capture efficiency of quantum dots, which is very beneficial for omnidirectional light detection and wide-angle imaging applications. Compared with other geometric structures, the spherical structure can distribute heat more evenly, reducing the risk of local heat accumulation, thereby protecting the performance and stability of quantum dots. Inside the spherical structure, the light transmission path can be optimized to reduce unnecessary losses. This enables quantum dots to utilize incident light more efficiently and improve the photoelectric conversion efficiency.

[0017] The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A photodetector of nano-spherical quantum dots, characterized in that: The invention comprises a GaAs substrate, on which an N-type doping layer, a quantum dot layer and a P-type doping layer are epitaxially grown layer by layer, an ITO film layer is formed on the surface of the P-type doping layer, a metal bottom electrode film layer is formed under the GaAs substrate, and the quantum dot layer is an orderly arranged nano spherical structure.

2. The photodetector of nano-spherical structure quantum dots according to claim 1, characterized in that: The nanosphere structure is obtained by processing the quantum dot layer through nanosphere photolithography and etching processes.

Images