重庆师范大学李万俊教授团队（宽带隙半导体材料与器件团队）在自供电Ga2O3基日盲紫外光电探测器研究中取得进展。该团队通过构筑Pt/a-Ga2O3/ITO垂直型肖特基结构，实现了高性能自供电日盲紫外光电探测器。相关成果以"Self-powered Pt/a-Ga2O3/ITO vertical Schottky junction solar-blind photodetector with excellent detection performance"为题发表在国际著名光学核心期刊《Optics Express》杂志上。团队研究生叶力予为第一作者，熊元强副教授和李万俊教授为共同通讯作者。
自供电日盲光电探测器（PD）具有操作方便、易于制备和弱光灵敏度高等优点，在军事和民用领域的应用前景广阔。本研究通过使用低成本的磁控溅射技术，提出了具有简单垂直叠层结构的非晶Ga2O3(a-Ga2O3)基日盲深紫外光电探测器。通过调整非晶Ga2O3层的厚度，该器件表现出卓越的探测性能。在3 V反向偏压下，该光电探测器实现了671 A/W的高响应率、2.21×1015 Jones的高探测率和27/11 ms的快速响应时间。更难能可贵的是，在界面处内建电场的帮助下，该器件在自供电时展现了出色的性能，在254 nm光照下具有3.69 A/W的超高响应率和2.6/6.6 ms的快速响应时间。这些结果优于迄今报道的大多数自供电肖特基结紫外光电探测器。最后，Pt/a-Ga2O3/ITO肖特基结光电二极管探测器在成像方面表现出色，表明其适用于在日盲深紫外成像等领域的适用性。
Fig. 1. I-T characters of the a-Ga2O3 thin film-based photodetector of different thicknesses under 254 nm illumination with a light intensity of 500 µW/cm2. (b) Photocurrents, (c) Responsivity and (d) PDCR of a-Ga2O3 films of different thicknesses under 254 nm illumination with a light intensity of 500 µW/cm2 at −3 V.
Fig. 2. (a) The XRD pattern of a-Ga2O3 film. (b) Absorption spectrum and optical direct bandgap of a-Ga2O3 film. (c) Cross-sectional SEM images of Pt/Ga2O3/ITO the PD. (d) Element line sweep of Pt/a-Ga2O3/ITO the PD cross-section.
Fig. 3. (a) I-V characters of the a-Ga2O3 thin film-based photodetector in dark and under 254 nm light illumination with different intensities. (b) Responsivity and Detectivity of the device as functions of light intensity at −3 V. (c) Photocurrent and PCDR of the device as functions of light intensity at −3 V. (d) I-t curve of the device under 254 nm light with different illumination intensities and 365 nm illumination (100 µW/cm2) at −3 V. (e) Response time of PD under −3 V and 254 nm light with 500µW/cm2 light intensity. (f) The photocurrent response of the photodetector with −3 V bias under illumination of 254 nm light with an intensity of 300 µW/cm2.
Fig. 4. (a) I-t curve of the device under 254 nm light with different illumination intensities at 0 V. (b) Responsitity, (c) Detectivity and (d) PDCR of the device as functions of light intensity at 0 V. (e) Response time of PD under 254 nm and 0 V. (f) The photocurrent response of the photodetector with 0 V bias under illumination of 254 nm light with an intensity of 300 µW/cm2.
Fig. 5. (a) Energy band diagram of Pt/a-Ga2O3/ITO heterojunction. (b) Pt, a- Ga2O3, and ITO brought into intimate contact to form a back-to-back Schottky heterojunction. (c) the heterojunction under 254 nm light.
Fig. 6. (a) Schematic diagram of the set up for the solar-blind imaging using DUV. (b) The 2D current contrast mapping of the photodetectors array in the dark. 2D current contrast mapping of array under 254 nm light (500 µW/cm2) at (c) −3 V and (d) 0 V.
Table 1. Comparison of key parameters of Ga2O3 solar-blind PDs.
论文信息：
Liyu Ye#, Shuren Zhou#, Yuanqiang Xiong*, Jie Tang, Xuan Wang, Xudong Li, Di Pang, Honglin Li, Hong Zhang, Lijuan Ye, Yuting Cui, Wanjun Li*. Self-powered Pt/a-Ga2O3/ITO vertical Schottky junction solar-blind photodetector with excellent detection performance. Optics Express, 2023, 31: 28200.
论文链接：
https://doi.org/10.1364/OE.494216.
重庆师范大学宽禁带半导体材料与器件团队
https://www.x-mol.com/groups/li_wanjun
