Efficient Self‐Driven Photodetectors Featuring a Mixed‐Dimensional van der Waals Heterojunction Formed from a CdS Nanowire and a MoTe2 Flake |
| |
| Authors: | Ming‐Yen Lu Yung‐Ting Chang Hsin‐Ju Chen |
| |
| Affiliation: | 1. Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan;2. High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan;3. Graduate Institute of Opto‐Mechatronics, National Chung Cheng University, Chia‐Yi, Taiwan |
| |
| Abstract: | Heterojunctions formed from low‐dimensional materials can result in photovoltaic and photodetection devices displaying exceptional physical properties and excellent performance. Herein, a mixed‐dimensional van der Waals (vdW) heterojunction comprising a 1D n‐type Ga‐doped CdS nanowire and a 2D p‐type MoTe2 flake is demonstrated; the corresponding photovoltaic device exhibits an outstanding conversion efficiency of 15.01% under illumination with white light at 650 µW cm?2. A potential difference of 80 meV measured, using Kelvin probe force microscopy, at the CdS–MoTe2 interface confirms the separation and accumulation of photoexcited carriers upon illumination. Moreover, the photodetection characteristics of the vdW heterojunction device at zero bias reveal a rapid response time (<50 ms) and a photoresponsivity that are linearly proportional to the power density of the light. Interestingly, the response of the vdW heterojunction device is negligible when illuminated at 580 nm; this exceptional behavior is presumably due to the rapid rate of recombination of the photoexcited carriers of MoTe2. Such mixed‐dimensional vdW heterojunctions appear to be novel design elements for efficient photovoltaic and self‐driven photodetection devices. |
| |
| Keywords: | Kelvin probe force microscopy mixed‐dimensional van der Waals heterojunction p– n junction self‐driven photodetector |
|
|
