High-performance Flexible Broadband Photodetectors Based on 2D Hafnium Selenosulfide Nanosheets

Rajesh Kumar Ulaganathan^1*

¹Center for Condensed Matter Science, National Taiwan University, Taipei, Taiwan

* Presenter:Rajesh Kumar Ulaganathan, email:urajeshiitr@gmail.com

2D Transition-metal dichalcogenides (TMDC) have attracted significant interest in recent years due to its multiple degrees of freedom on tuning the physical properties via band engineering and dimensionality adjustment. We report the study of ternary 2D hafnium selenosulfide HfSSe (HSS) high-quality single crystals grown with the chemical vapor transport (CVT) technique. The as-grown HSS single crystal exhibits excellent phototransistor performance from the visible to the near-infrared (NIR) spectral range with outstanding stability. A giant photoresponsivity (~6.4×104 A/W at 488 nm) and high specific detectivity (~1014 Jones) were obtained from the device fabricated with exfoliating single crystal HSS of nano-thickness on a rigid Si/SiO2 substrate. The application of HSS single crystal is extended to yield a sensible flexible photodetector of photoresponsivity up to ~1.3 A/W at 980 nm. The photoresponsivity of CVT grown HSS single crystal is significantly larger than those fabricated with other existing Hf-based chalcogenides. Our results suggest that the layered multi-elemental 2D chalcogenide single crystals hold great promise for future wearable electronics and integrated optoelectronic circuits.

Keywords: Crystal Growth, Photoresponsivity, Specific Detectivity, Flexible Optoelectronics