Graphene/silicon dioxide/silicon based avalanche photodetector and preparation method

Abstract

The invention discloses a graphene / silicon dioxide / silicon based avalanche photodetector and a preparation method thereof. The avalanche photodetector comprises an n-type silicon substrate, a silicon dioxide isolation layer, a silicon dioxide window, a silicon dioxide insulating layer, a top electrode, a graphene thin film and a bottom electrode. The avalanche photodetector can carry out wide-spectrum detection, thereby solving a problem of low response of traditional silicon substrate PIN nodes for ultraviolet light detection. The detector takes graphene as an active layer and a transparent electrode, thereby removing a dead layer, and enhancing absorption for incident light. The silicon dioxide insulating layer reduces influences of the silicon surface state, and suppresses reverse saturation current at the same time. Photon-generated carriers collide with silicon lattices under an effect of high reverse bias voltage and are ionized, and a very high gain is acquired. The preparation technology adopted by the invention is simple, the cost is low, and the avalanche photodetector has the characteristics of high response degree, high response speed, large internal gain, small switch ratio and easy integration.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and relates to a photoelectric detection device structure, in particular to a graphene / silicon dioxide / silicon-based avalanche photodetector (APD) and a preparation method. Background technique [0002] Optical detectors have a wide range of applications in chemical material analysis, medical and health care, and space technology. Avalanche photodetectors have the advantages of high sensitivity, high optical response, and fast response speed, and have important applications in high-speed modulation and weak signal monitoring. Traditional silicon-based PIN junction detectors require thermal diffusion or ion implantation processes, and there is a dead layer problem for ultraviolet light, and the response decreases rapidly as the wavelength of the incident light decreases. Therefore, there is a need to improve the response of silicon photodetector devices to short-wavelength visible...

AI Technical Summary

Problems solved by technology

The dark current of the Schottky structure detector is greater than that of the PIN structure device. The dark current of the device is a very important parameter, which affects the noise of the device, which inhibits the development of the Schottky structure detector to a certain extent.

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