Engineered s-SWCNT network/a-Ga2O3 heterointerface for enhanced deep ultraviolet photodetection

Abstract

Amorphous gallium oxide (a-Ga₂O₃) is promising for deep-ultraviolet photodetection due to its wide bandgap, but its performance is limited by inefficient carrier separation and transport. Here, we design a solution-processed semiconducting single-walled carbon nanotube (s-SWCNT)/a-Ga₂O₃ heterojunction via spin-coating and magnetron sputtering, achieving a record responsivity of 1.4 A W⁻¹ and external quantum efficiency (671%) at 260 nm—two orders of magnitude higher than pristine a-Ga₂O₃. Key mechanistic insights reveal that while the interface forms a Type-I band alignment for carrier injection, the s-SWCNT network provides an efficient charge transport pathway. This dual functionality enhances photogenerated carrier separation and collection, overcoming conventional limitations. Our work not only elucidates the charge dynamics in s-SWCNT/a-Ga₂O₃ heterojunctions but also offers a scalable, cost-effective fabrication strategy combining solution processing and sputtering. This approach can be extended to other narrow/wide-bandgap heterostructures for next-generation optoelectronics.