Wen Junjie, Wang Yuankang, Zhang Biao, Chen Rongrong, Zhu Hongyan, Han Xinyu, Xiao Hongdi
School of Integrated Circuits, Shandong University, Jinan 250100, China.
Nanomaterials (Basel). 2024 Jul 8;14(13):1165. doi: 10.3390/nano14131165.
The utilization of a nanoporous (NP) GaN fabricated by electrochemical etching has been demonstrated to be effective in the fabrication of a high-performance ultraviolet (UV) photodetector (PD). However, the NP-GaN PD typically exhibits a low light-dark current ratio and slow light response speed. In this study, we present three types of UV PDs based on an unetched GaN, NP-GaN distributed Bragg reflector (DBR), and NP-GaN-DBR with a GaO single-crystal film (GaO/NP-GaN-DBR). The unetched GaN PD does not exhibit a significant photoresponse. Compared to the NP-GaN-DBR PD device, the GaO/NP-GaN-DBR PD demonstrates a larger light-dark current ratio (6.14 × 10) and higher specific detectivity (8.9 × 10 Jones) under 365 nm at 5 V bias due to its lower dark current (3.0 × 10 A). This reduction in the dark current can be attributed to the insertion of the insulating GaO between the metal and the NP-GaN-DBR, which provides a thicker barrier thickness and higher barrier height. Additionally, the GaO/NP-GaN-DBR PD device exhibits shorter rise/decay times (0.33/0.23 s) than the NP-GaN-DBR PD, indicating that the growth of a GaO layer on the DBR effectively reduces the trap density within the NP-GaN DBR structure. Although the device with a GaO layer presents low photoresponsivity (0.1 A/W), it should be feasible to use GaO as a dielectric layer based on the above-mentioned reasons.
通过电化学蚀刻制备的纳米多孔（NP）氮化镓已被证明在高性能紫外（UV）光电探测器（PD）的制造中是有效的。然而，NP-GaN PD通常表现出较低的明暗电流比和较慢的光响应速度。在本研究中，我们展示了三种基于未蚀刻GaN、NP-GaN分布布拉格反射器（DBR）以及带有GaO单晶膜的NP-GaN-DBR（GaO/NP-GaN-DBR）的紫外PD。未蚀刻的GaN PD没有显著的光响应。与NP-GaN-DBR PD器件相比，由于其较低的暗电流（3.0×10 A），GaO/NP-GaN-DBR PD在5 V偏压下365 nm处表现出更大的明暗电流比（6.14×10）和更高的比探测率（8.9×10琼斯）。暗电流的降低可归因于在金属和NP-GaN-DBR之间插入了绝缘的GaO，这提供了更厚的势垒厚度和更高的势垒高度。此外，GaO/NP-GaN-DBR PD器件的上升/下降时间（0.33/0.23 s）比NP-GaN-DBR PD短，这表明在DBR上生长GaO层有效地降低了NP-GaN DBR结构内的陷阱密度。尽管带有GaO层的器件具有低光响应度（0.1 A/W），但基于上述原因，将GaO用作介电层应该是可行的。
