| Autor: |
Yang YT; Design and Materials for Medical Equipment and Devices, Da-Yeh University, Changhua 515006, Taiwan., Lin SC; Mechanical and Mechatronics System Research Labs, Industrial Technology Research Institute, Hsinchu 310401, Taiwan., Wang CC; Mechanical and Mechatronics System Research Labs, Industrial Technology Research Institute, Hsinchu 310401, Taiwan., Ho YR; Department of Electrical Engineering, Da-Yeh University, Changhua 515006, Taiwan., Chen JZ; Graduate Institute of Photonics, National Changhua University of Education, Changhua 50007, Taiwan., Huang JJ; Department of Electrical Engineering, Da-Yeh University, Changhua 515006, Taiwan. |
| Abstrakt: |
This study employed atomic layer deposition (ALD) to fabricate an Al 2 O 3 passivation layer to optimize the performance of ultraviolet (UV) photodetectors with a TiO 2 -nanorod-(NR)-containing active layer and a solid-liquid heterojunction (SLHJ). To reduce the processing time and enhance light absorption, a hydrothermal method was used to grow a relatively thick TiO 2 -NR-containng working electrode. Subsequently, a 5-nm-thick Al 2 O 3 passivation layer was deposited on the TiO 2 NRs through ALD, which has excellent step coverage, to reduce the surface defects in the TiO 2 NRs and improve the carrier transport efficiency. X-ray photoelectron spectroscopy revealed that the aforementioned layer reduced the defects in the TiO 2 NRs. Moreover, high-resolution transmission electron microscopy indicated that following the annealing treatment, Al, Ti, and O atoms diffused across the interface between the Al 2 O 3 passivation layer and TiO 2 NRs, resulting in the binding of these atoms to form Al-Ti-O bonds. This process effectively filled the oxygen vacancies in TiO 2 . Examination of the photodetector device revealed that the photocurrent-to-dark current ratio exhibited a difference of four orders of magnitude (10 -4 to 10 -8 A), with the switch-on and switch-off times being 0.46 and 3.84 s, respectively. These results indicate that the Al 2 O 3 passivation layer deposited through ALD can enhance the photodetection performance of SLHJ UV photodetectors with a TiO 2 active layer. |
