Consecutive Junction-Induced Efficient Charge Separation Mechanisms for High-Performance MoS<sub>2</sub>/Quantum Dot Phototransistors.
Morris, Stephen M
ACS applied materials & interfaces
American Chemical Society
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Pak, S., Cho, Y., Hong, J., Lee, J., Lee, S., Hou, B., An, G., et al. (2018). Consecutive Junction-Induced Efficient Charge Separation Mechanisms for High-Performance MoS<sub>2</sub>/Quantum Dot Phototransistors.. ACS applied materials & interfaces, 10 (44), 38264-38271. https://doi.org/10.1021/acsami.8b14408
Phototransistors that are based on a hybrid vertical heterojunction structure of two-dimensional (2D)/quantum dots (QDs) have recently attracted attention as a promising device architecture for enhancing the quantum efficiency of photodetectors. However, to optimize the device structure to allow for more efficient charge separation and transfer to the electrodes, a better understanding of the photophysical mechanisms that take place in these architectures is required. Here, we employ a novel concept involving the modulation of the built-in potential within the QD layers for creating a new hybrid MoS2/PbS QDs phototransistor with consecutive type II junctions. The effects of the built-in potential across the depletion region near the type II junction interface in the QD layers are found to improve the photoresponse as well as decrease the response times to 950 μs, which is the faster response time (by orders of magnitude) than that recorded for previously reported 2D/QD phototransistors. Also, by implementing an electric-field modulation of the MoS2 channel, our experimental results reveal that the detectivity can be as large as 1 × 1011 jones. This work demonstrates an important pathway toward designing hybrid phototransistors and mixed-dimensional van der Waals heterostructures.
The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007−2013)/ERC Grant Agreement no. 340538. This work was also supported by the National Research Foundation of Korea (NRF) (2015M2A2A6A02045252) and Samsung Global Research Outreach (Samsung GRO) program. In addition, S.M.M. would like to thank The Royal Society for financial support.
European Commission Horizon 2020 (H2020) ERC (340538)
External DOI: https://doi.org/10.1021/acsami.8b14408
This record's URL: https://www.repository.cam.ac.uk/handle/1810/295259