1. An Ultrafast WSe2 Photodiode Based on a Lateral p-i-n Homojunction
- Author
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Chun Zhao, Changjiang Nie, Youwei Zhang, Wei Hong, Shun Wang, Zhi-Jun Qiu, and Ma Kankan
- Subjects
Materials science ,business.industry ,General Engineering ,General Physics and Astronomy ,Photodetector ,02 engineering and technology ,Photodetection ,Specific detectivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Photodiode ,law.invention ,Responsivity ,law ,Optoelectronics ,General Materials Science ,Electrical measurements ,Homojunction ,0210 nano-technology ,business ,Diode - Abstract
High-quality homogeneous junctions are of great significance for developing transition metal dichalcogenides (TMDs) based electronic and optoelectronic devices. Here, we demonstrate a lateral p-type/intrinsic/n-type (p-i-n) homojunction based multilayer WSe2 diode. The photodiode is formed through selective doping, more specifically by utilizing self-aligning surface plasma treatment at the contact regions, while keeping the WSe2 channel intrinsic. Electrical measurements of such a diode reveal an ideal rectifying behavior with a current on/off ratio as high as 1.2 × 106 and an ideality factor of 1.14. While operating in the photovoltaic mode, the diode presents an excellent photodetecting performance under 450 nm light illumination, including an open-circuit voltage of 340 mV, a responsivity of 0.1 A W-1, and a specific detectivity of 2.2 × 1013 Jones. Furthermore, benefiting from the lateral p-i-n configuration, the slow photoresponse dynamics including the photocarrier diffusion in undepleted regions and photocarrier trapping/detrapping due to dopants or doping process induced defect states are significantly suppressed. Consequently, a record-breaking response time of 264 ns and a 3 dB bandwidth of 1.9 MHz are realized, compared with the previously reported TMDs based photodetectors. The above-mentioned desirable properties, together with CMOS compatible processes, make this WSe2p-i-n junction diode promising for future applications in self-powered high-frequency weak signal photodetection.
- Published
- 2021