Enhanced linear dynamic range and response speed in interdigital-electrode solar-blind photodetector by contact engineering
Kangren Sang, Jiayun Wei, Wei Han, Ziyu Chu, Hui Yuan, Chenguang Guo, Jinlong Liu, Qihang Sun, Longhui Zeng, Lu Shen, Jun Yuan, Qiangmin Wei, Hao Wang
Abstract
As an ultra-wide bandgap semiconductor, gallium oxide (Ga2O3) has great market potential in the field of solar-blind UV photodetectors. However, the slow response time of hundreds of milliseconds has seriously hindered the commercialization of the Ga2O3 photodetector. Here, we design an interdigital-electrode solar-blind UV β-Ga2O3 photodetector by using high-work function metal Pd as contacts. The atomic transmission electron microscopy data reveal that the Pd-Ga2O3 interface is clean and smooth, composed of a Ga2O3 single crystal and a local Pd single crystal, beneficial for weakening Fermi-level pinning. A low-damage and low-defect contact interface provides an excellent photoelectric response time of 2.4 ms (rise)/2.6 ms (descend) and a large linear dynamic range of 140 dB. On a 2-in. wafer of β-Ga2O3 film, we made a 12 × 12 array in which all 64 (8 × 8) devices tested maintained consistent performance and high reliability. Our high-performance Pd-Ga2O3 interdigital-electrode solar-blind photodetectors provide assurance for UV communication and imaging applications.