WS2/WO3 Heterostructure-Based Photodetectors on SiO2/Si for Future Optoelectronics

Photodetectors are becoming indispensable compo-nents in next-generation optoelectronic devices and photonic integrated circuits. Emerging materials like transition metal dichalcogenides (TMDs) are suitable for broad-band photo-detectors owing to their significant properties like high carrier mobility, bandgap tunability, flexibility, and integration. Herein, we report a strategic development of WS2/WO3 heterostructures by sputtering and chemical vapor deposition techniques to fabricate a metal-semiconductor-metal planar-structured Ag/WS2/WO3/Ag photodetector device with interdigitated Ag electrodes. A comparative study has been made based on the photodetector performance between the WS2/WO3 heterostructure and pristine WO3 and WS2 thin-film-based devices. The WS2/WO3 heterostructure shows a responsivity of 2.94 and 2.02 A/W under a UV intensity of 0.66 mW/cm2 and a visible intensity of 0.58 mW/cm2 illuminations, respectively. In this heterostructure, the WS2 layer helps in trapping the photo-excited charge carriers from WO3 and also reduces the recombination losses by absorbing the emitted radiation with WO3. The simple interdigitated electrodes allowed the WS2/WO3 test device to achieve a quick response and recovery time of 100 ms. A similar approach can be realized to fabricate the other TMD-based hybrid heterostructures for enhanced performance of real-life broad-band photodetector applications.