Greatly improved photoresponse in the MAPbBr/Si heterojunction by introducing an ITO layer and optimizing MAPbBr layer thickness.

In this paper, a CHNH(MA)PbBr/Si heterojunction photodetector (PD) is prepared, and a simple method is proposed to improve the performance by introducing an ITO conductive layer and modulating thickness of the MAPbBr layer. The results indicate that the MAPbBr/Si heterojunction PD exhibits an ultra-broadband photoresponse ranging from 405 to 1064 nm, and excellent performances with the responsivity (R) of 0.394 mA/W, detectivity (D) of 0.11×10 Jones, and response times of ∼2176/∼257 ms. When adding the ITO layer, the R and D are greatly improved to 0.426 A/W and 5.17×10 Jones, which gets an increment of 1.08×10% and 4.7×10%, respectively. Meanwhile, the response times are reduced to ∼130/∼125 ms, and a good environmental stability is obtained. Moreover, it is found that the photoresponse is strongly dependent on the thickness of the MAPbBr layer. By modulating the MAPbBr layer thickness from ∼85 to ∼590 nm, the performances are further improved with the best R of ∼0.87 A/W, D of ∼1.92×10 Jones, and response times of ∼129/∼130 ms achieved in the ∼215 nm-thick PD.