Self-Powered High-Performance WS<sub>2</sub> Photodetector via a Monolithic p-i-n Homojunction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40892538.
- Also identified by DOI 10.1021/acs.nanolett.5c03066 and PMC identifier 12447547.
- Licence recorded as CC BY-NC-ND.
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Abstract
Lateral homojunction photodetectors (PDs) offer high responsivity and fast response, yet challenges in tailoring carrier concentrations in two-dimensional transition-metal dichalcogenides (TMDs) have limited their implementation. Here, we demonstrate a high-performance self-powered monolithic lateral p-i-n homojunction PD using multilayer WS<sub>2</sub>. To our knowledge, this study is the first report of achieving tunable, multilevel compensation doping via WO<sub>X</sub> formation using only time-controlled and region-selective ultraviolet (UV)/ozone oxidation. The oxidation process transforms WS<sub>2</sub> through distinct phases: initial WO<sub>X</sub> (2 < X < 3) formation with thickness growth (0-90 min), increased WO<sub>3</sub> ratio without thickness change (90-120 min), and self-limited saturation (>120 min). Photocurrent mapping confirms the formation of a lateral p-i-n homojunction, achieving a responsivity of 471 mA/W at 530 nm, a rejection ratio of 200, and response times of ∼4.5 ms under photovoltaic-mode operation. This study enables precise control of free carrier concentrations in TMDs, paving the way to versatile monolithic homojunction optoelectronic devices.