Work

Self‐Powered Photodetection and Optical Information Recognition in a Mixed‐Dimensional WSe 2 /CdSe Heterojunction

Year: 2026

Type: article

Abstract: ABSTRACT Mixed‐dimensional van der Waals heterojunctions offer opportunities for self‐powered optical sensing and information processing, yet identifying the spatial origin of zero‐bias photoresponse remains important for understanding device operation. Here, a vertical WSe 2 /CdSe heterojunction composed of a WSe 2 nanosheet and a CdSe nanobelt is investigated for visible photodetection. Under 610 nm illumination, the device exhibits a photovoltaic response with an open‐circuit voltage of 0.403 V and a short‐circuit current of 4.77 × 10 −10 A. Quantitative photocurrent mapping reveals a mean response of 5.94 nA in the heterojunction overlap region, approximately 50 times that near the metal contacts. Scanning Kelvin probe microscopy yields a reproducible contact‐potential‐difference contrast of 293 ± 15 mV, whereas electronic‐structure calculations support a type‐II band‐edge configuration and interfacial charge redistribution. At 100 Hz, the measured rise/fall times are 1.09/0.99 ms at 0 V and 165/191 μs at +3 V. Under +3 V bias, approximately 97% of the reference modulation amplitude is retained at 1 kHz. Self‐powered optical imaging and wavelength‐ and time‐window‐dependent 8‐bit information recognition are further demonstrated, with all 96 tested bits correctly decoded. These results highlight the potential of mixed‐dimensional WSe 2 /CdSe heterojunctions for self‐powered visible‐light sensing and optical information recognition.

Source: Nanophotonics

DOI: 10.1002/nap2.70362