Consecutive Junction-Induced Efficient Charge Separation Mechanisms for High-Performance MoS2/Quantum Dot Phototransistors

• DOI: 10.1021/acsami.8b14408
• Publication Date: 2018-10-19T13:37:57Z
• Authors: Sangyeon Pak; Yuljae Cho; John Hong; Juwon Lee; Sanghyo Lee; Bo Hou; Geon-Hyoung An; Young-Woo Lee; Jae Eun Jang; Hyunsik Im; Stephen M. Morris; Jung Inn Sohn; SeungNam Cha; Jong Min Kim
• Keywords: Photodiode; Quantum Efficiency; Depletion region; Modulation (music)

Phototransistors that are based on a hybrid vertical heterojunction structure of two-dimensional (2D)/quantum dots (QDs) have recently attracted attention as promising device architecture for enhancing the quantum efficiency photodetectors. However, to optimize allow more efficient charge separation and transfer electrodes, better understanding photophysical mechanisms take place in these architectures is required. Here, we employ novel concept involving modulation built-in potential within QD layers creating new MoS2/PbS QDs phototransistor with consecutive type II junctions. The effects across depletion region near junction interface found improve photoresponse well decrease response times 950 μs, which faster time (by orders magnitude) than recorded previously reported 2D/QD phototransistors. Also, by implementing an electric-field MoS2 channel, our experimental results reveal detectivity can be large 1 × 1011 jones. This work demonstrates important pathway toward designing phototransistors mixed-dimensional van der Waals heterostructures.