A device with two kinds of functions —Ultraviolet photodetector and electroluminescence: Fabrication and carrier transport mechanism

Hai Zhou, Guojia Fang^a, Yongdan Zhu, Nishuang Liu, Haoning Wang, Huihui Huang, Songzhan Li and Xingzhong Zhao

Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education of China and Department of Electronic Science and Technology, School of Physics and Technology, Wuhan University - Wuhan 430072, PRC

^a gjfang@whu.edu.cn

Received: 14 October 2011
Accepted: 13 February 2012

Abstract

We reported an n-ZnO/n-GaN heterojunction device in which both ultraviolet (UV) detecting and electroluminescence performances of the device are controlled by the applied forward-bias voltage. For ZnO-based UV photodetectors, our devices showed excellent photoresponse characteristics with detectivity of ∼2.80×10¹³ cm Hz^1/2/W and responsivity of ∼276 A/W at 2 V. UV and visible electroluminescences of the device were also observed. Also, a Mn:ZnO/GaN heterojunction had been prepared and it also possessed the two functions. Furthermore, the Mn:ZnO/GaN device showed better UV detectivity and enlarged the visible emission. The reason for our devices possessing two functions had been explored through the carrier transport mechanism and the channel current formation diagram.