High-Performance Broadband Phototransistor Based on TeO x /IGTO Heterojunctions.

Ultraviolet to infrared broadband spectral detection capability is a technological challenge for sensing materials being developed for high-performance photodetection. In this work, we stacked 9 nm-thick tellurium oxide (TeO x ) and 8 nm-thick InGaSnO (IGTO) into a heterostructure at a low temperature of 150 °C. The superior photoelectric characteristics we achieved benefit from the intrinsic optical absorption range (300-1500 nm) of the hexagonal tellurium (Te) phase in the TeO x film, and photoinduced electrons are driven effectively by band alignment at the TeO x /IGTO interface under illumination. A photosensor based on our optimized heterostructure exhibited a remarkable detectivity of 1.6 × 10 13 Jones, a responsivity of 84 A/W, and a photosensitivity of 1 × 10 5 , along with an external quantum efficiency of 222% upon illumination by blue light (450 nm). Simultaneously, modest detection properties (responsivity: ∼31 A/W, detectivity: ∼6 × 10 11 Jones) for infrared irradiation at 970 nm demonstrate that this heterostructure can be employed as a broadband phototransistor. Furthermore, its low-temperature processability suggests that our proposed concept might be used to design array optoelectronic devices for wide band detection with high sensitivity, flexibility, and stability.