High‐Responsivity Graphene/4H‐SiC Ultraviolet Photodetector Based on a Planar Junction Formed by the Dual Modulation of Electric and Light Fields. Issue 19 (6th July 2020)

• Record Type: Journal Article
• Authors: Li, Yimeng; Chen, Peng; Chen, Xiufang; Xu, Ru; Liu, Menghan; Zhou, Jing; Ge, Cheng; Peng, Haocheng; Mao, Xiaokang; Feng, Jianbo; Hu, Xiaobo; Peng, Yan; Xu, Xiangang; Xie, Zili; Xiu, Xiangqian; Chen, Dunjun; Liu, Bin; Han, Ping; Shi, Yi; Zhang, Rong; Zheng, Youdou
• Is Part Of: Advanced optical materials. Volume 8:Issue 19(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-07-06
• Subjects: graphene -- photoconductive gain -- planar junctions -- SiC -- ultraviolet photodetectors; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202000559
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Ultraviolet (UV) photodetectors have been fabricated on a graphene/4H‐SiC wafer. In this device, the electrical doping in the graphene layer, under the gate, is realized by changing the gate voltage while the optical doping in the graphene layer outside the gate region is realized through the photogenerated carrier injection from SiC, by laser excitation at 325 nm. This kind of dual modulation of optical and electric fields ultimately results in the formation of a planar n–p–n or n–n–n junction in the graphene layer. The photoresponse results demonstrate that the planar n–p–n junction is formed at the negative gate voltage, and facilitates negative photoconductivity. The n–n–n junction is formed at the positive gate voltage and facilitates normal photoconductivity. The maximum responsivity, which is attributable to the high photoconductive gain in the planar n–n–n junction, is 254.1A W −1, at drain‐source voltage of −3 V and gate‐source voltage of 3 V. Based on these results, the estimated lifetime of the electrons in the graphene channel extends greatly to more than four orders of magnitude longer than that in the isolated graphene. The above results prove that this graphene/4H‐SiC combined structure possesses great potential in practical UV‐detection applications. Abstract : A high‐response ultraviolet photodetector has been fabricated on a graphene/4H‐SiC wafer. The graphene channel can be doped by a combination of light and electric fields, resulting in the planar graphene n–p–n or n–n–n junction. High responsivity has been achieved with the maximum value of 254.1 A W −1 by forming the n–n–n planar junction.