Band Structure Engineering in MoS<sub>2</sub> Based Heterostructures toward High‐Performance Phototransistors
Haoting Ying, Xin Li, Hemiao Wang, Yurui Wang, Xin Hu, Jian Zhang, Xuefeng Zhang, Yueqin Shi, Minxuan Xu, Qi Zhang
Abstract
Abstract Interfacial band structure engineering paves a promising route to promote the application of 2D semiconductors in optoelectronics, and thereby in the last decades, a great number of studies about heterojunction based on transition‐metal dichalcogenides (TMDs) have been implemented. Most of the latest photodetectors mainly consist of a type II band alignment in which, however, the interfacial emission quenching leads to a higher nonradiative rate, an awkward problem for reducing their energy consumption. Here, BaTiO 3 /MoS 2 heterostructures with type I band alignment fabricated by a facile spin‐coating method are reported, and their remarkable photodetection performance in comparison with devices based on bare MoS 2 ( R λ : 120 A W −1 vs 1.7 A W −1 and external quantum efficiency (EQE): 4.78 × 10 4 % vs 4.5 × 10 2 % @365 nm) is demonstrated. Optical measurements including micro‐Raman and photoluminescence (PL) suggest a carrier extraction process accompanied by the carrier injection occurring in the narrower‐bandgap (MoS 2 ) layer, responsible for the increment of carrier population in MoS 2 channel and subsequent improvement of detection ability. Hence, the demonstration of such 0D/2D type‐I heterostructures through an interfacial control provides valuable information for developing low cost yet superior performance optoelectronic devices in future.