Chu Shao-Yu, Shen Meng-Xian, Yeh Tsung-Han, Chen Chia-Hsun, Lee Ching-Ting, Lee Hsin-Ying
Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan.
Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 335, Taiwan.
Sensors (Basel). 2020 Oct 29;20(21):6159. doi: 10.3390/s20216159.
In this work, GaO films were deposited on sapphire substrates using a plasma-enhanced atomic layer deposition system with trimethylgallium precursor and oxygen (O) plasma. To improve the quality of GaO films, they were annealed in an O ambient furnace system for 15 min at 700, 800, and 900 °C, respectively. The performance improvement was verified from the measurement results of X-ray diffraction, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The optical bandgap energy of the GaO films decreased with an increase of annealing temperatures. Metal-semiconductor-metal ultraviolet C photodetectors (MSM UVC-PDs) with various GaO active layers were fabricated and studied in this work. The cut-off wavelength of the MSM UVC-PDs with the GaO active layers annealed at 800 °C was 250 nm. Compared with the performance of the MSM UVC-PDs with the as-grown GaO active layers, the MSM UVC-PDs with the 800 °C-annealed GaO active layers under a bias voltage of 5 V exhibited better performances including photoresponsivity of 22.19 A/W, UV/visible rejection ratio of 5.98 × 10, and detectivity of 8.74 × 10 cmHzW.
在本工作中，使用配备三甲基镓前驱体和氧气（O）等离子体的等离子体增强原子层沉积系统在蓝宝石衬底上沉积GaO薄膜。为了提高GaO薄膜的质量，分别在700、800和900℃的O气氛炉系统中对其进行15分钟的退火处理。通过X射线衍射、X射线光电子能谱和光致发光光谱的测量结果验证了性能的提升。GaO薄膜的光学带隙能量随着退火温度的升高而降低。在本工作中制备并研究了具有不同GaO有源层的金属-半导体-金属紫外C光电探测器（MSM UVC-PD）。在800℃退火的具有GaO有源层的MSM UVC-PD的截止波长为250nm。与具有生长态GaO有源层的MSM UVC-PD的性能相比，在5V偏置电压下，具有800℃退火GaO有源层的MSM UVC-PD表现出更好的性能，包括22.19 A/W的光响应度、5.98×10的紫外/可见光抑制比以及8.74×10 cmHzW的探测率。
