A clean, smooth interface between a gallium oxide hauler and palladium electrodes improves the performance of ultraviolet solar blind photo setectors.
Gallium oxide is a promising material for solar blind-ultraviolet photoetectors that records short-wave ultraviolet light while ultraviolet
Ignore infrared, visible and longer ultraviolet light. These photo detectors have potential applications in optical communication, biomedical imaging, environmental monitoring, astrophysics and security.
However, the slow response time of Gallium oxide photo -detectors – hundreds of milliseconds – has hindered its commercial application. To remedy this, sang et al. Designed and constructed solar blind ultraviolet photodetectors using gallium oxide as a semiconductor and palladium as a contact electrode.
Previous photodetectors on a gallium oxide base often used titanium as a contact electrode. However, Palladium has a higher work function, which means that it needs more energy to remove electrons. This enables more precise control of the electron emission via its interface with gallium oxide.
“By using palladium electrodes with single crystal palladium, the performance of Gallium oxide-ultraviolet photo setectors was significantly improved,” said author Wei Han.
The photo detectors showed a faster photoelectric response time, 2.4 milliseconds and a larger linear dynamic range, which means that they can precisely identify light over a larger intensity range.
In addition to the selection of the materials, the quality of the interface between the semiconductor and the electrodes can influence the photo detector performance. Defects, contaminants and disorders at the interface slow down the device. The authors used high vacuum electron beam evaporation to reject the palladium electrodes on the surface of the gallium oxide. Transmission electron microscopy showed that the contact border area was clean and smooth.
The performance of these solar blind-ultraviolet photo detectors suggests that communication and imaging applications can be used in ultraviolet.
“Our next step will be to optimize the performance and carry out productization,” said the author Hao Wang.
Source: “Enhanced Linear Dynamic Range and Response Speed in Interdigital-Electrode Solar-Blind Photo-Tector by Contact Engineering,“ By Kangren Sang, Jiayun Wei, Wei Han, Ziyu Chu, Hui Yuan, Cheng Guo, Jinlong Liu, Qiang Sun, Longhui Zeng, Liangping Shen, Jun, Jun Yuan, Qiangmin Wei, and Hao Wang, Applied physics ratings (2025). The article can be accessed https://doi.org/10.1063/5.0269272 .