Photoelectric Properties Of Graphene And Its Detector Technology

Graphene, a two dimensional monolayer building block of a carbon allotrope, features high electron mobility, high transmittance, high thermal conductivity and adjustable Fermi energy. So it has many potential applications for electronic and optoelectronic devices, energy storage and sensor. Integrating graphene with semiconductor to form schottky junction can improve sensitivity and responsibility of device. However, due to the optical absorption in graphene/semiconductor is depletion in semiconductor, the spectral response of device is limited by the semiconductor material. So, we studied the photo-electronic properties of schottky junctions based on Graphene- In As/Ga As quantum dots hybrid structure in this paper, which can improve both the responsibility and spectral response. this paper mainly studied the following aspects:1) We review some significant experimental investigations on the rectifying metal/ semiconductor and graphene/semiconductor junction. We analyze the principles of the device and mechanism of the optical response.2) In order to form high quality schottky junctions based on Graphene- In As/Ga As quantum dots hybrid structure, we have optimized graphene wet transfer process and parameters of device fabrication.3) We studied temperature dependence of dark current properties of the schottky junctions based on Graphene- In As/Ga As quantum dots hybrid structure. The conduction voltage and the ideal factor of Schottky junction increase with the decrease of temperature. Schottky barrier height decreases with decreasing temperature. At room temperature, the ideal factor of the device is 2.6, and the barrier height is 0.69 e V.4) We have tested and analysed the photoresponse of the device under different incident light power and different bias. We discussed the mechanisms of the device in energy band theory.5) Under 0V bias voltage, the device shows photoresponse between 400nm-950 nm with the peak response of 0.18A/W.We study the schottky junctions based on Graphene- In As/Ga As quantum dots hybrid structure and discuss the influence of In As quantum dots on the properties of device. We further improve the photodetector based on graphene/semiconductor schottky junctions and optimize the process parameters. This article has great academic value to the fabrication of photosensor with fast response, low cost, wide spectrum and high quantum efficiency.