【Member News】Small methods----Research Group of Li Bingsheng from Northeast Normal University: β-Ga₂O₃/ GaN based pin high-detection-rate high-response-speed solar blind deep UV detector

      Professor Li Bingsheng, leading his research group on wide band gap semiconductor materials and devices, Key Laboratory of Ultraviolet Optical Emission Materials, Ministry of Education, Northeast Normal University, used the idea of reverse doping (Qin. Phys. B 2017,26 (11), 117101; J. Mater. Res. 2003,18,8), to successfully produce a high-spectrum ultraviolet detector with β-Ga₂O₃ / GaN of high crystal quality (Small 2023,2206664), by replacing the nitrogen in the GaN matrix with oxygen. Based on this, we introduce nitrogen-doped graphene as a hole transport layer and construct the NGr / Ga₂O₃ / GaN p-i-n heterojunction solar blind detector. The device has the advantages of high detection rate and fast response, and the detection index is similar to the commercial photomultiplier tubes. This result was published in Small Methods---an international journal (2023,2300041, https://doi.org/10.1002/smtd. 202300041), titled “Rapid Response Solar Blind Deep UV Photodetector with High Detectivity Based On Graphene: N/β-Ga₂O₃: N/GaN p-i-n Heterojunction Fabricated by a Reversed Substitution Growth Method”. The heterojunction showed an enhanced self-powered solar-blind detection capability, with a response time of 3.2μs (up) / /20 μs (down) and a detection rate of more than 10¹² Jones. At the reverse bias of 5V, the responsiveness is 8.3 A/W, a high dark ratio over 10⁶, and a detection rate ≈9×10¹⁴ Jones.

      The excellent performance of the device is attributed to: 1) the reverse substitution method to realize the effective doping of nitrogen in gallium oxide, introduce multi-hole holes, eliminate the interface barrier and control the transport direction of few tons; 2) the greater built-in potential in heterojunction due to the downshift of the Fermi level in β-Ga₂O₃; 3) the built-in electric field in β-Ga₂O₃ due to the introduction of p-type graphene with hole concentration up to ≈10²⁰cm^-3.

Figure 1: Detection rate of pin heterojunction device;The upper right inset shows the band diagram of NGr / Ga₂O₃ / GaN heterojunction;The lower right inset is the schematic diagram of the device

      The thesis was completed by Han Yurui, a doctoral student of Northeast Normal University, postdoctoral fellow Wang Yuefei as the co-first author, and Professor Li Bingsheng as the corresponding author. The project has been supported by the Major Research and Development Program of Transformational Technology of the Ministry of Science and Technology, and the General Project of the National Natural Science Foundation of China.

Reference:

[1]Y. Han, Y. Wang, D. Xia, S. Fu, C. Gao, J. Ma, H. Xu, B. Li, A. Shen, Y. Liu, Small Methods 2023, 2300041.

The original link:  https://doi.org/10.1002/smtd.202300041