Influence of electrode materials on molybdenum oxide/n-Si photodetectors

Until recently, different metals have been adopted as the electrode materials for MoO_x/Si photodetectors and solar cells, but the influence of these different metals has not been investigated. We have systematically studied and proved that the choice of metal has a great impact on optoelectronic performance. Ag and Al with similar low work functions display similar current-voltage behavior before and after the introduction of MoO_x; whereas Au and Ni which own similar high work functions lead to another type of current-voltage behavior. MoO_xin the metal/MoO_x/Si samples brings the superior diode behavior with an enhanced responsivity and decreased dark current as compared with the metal/Si samples. The choice of Ag as the top electrode on MoO_x/Si has low alloying or defect formation with the MoO_x/Si structure preventing the deterioration of the diode behavior, and the large downward band bending in MoO_xat the Ag/MoO_xjunction facilitates the multitunnelling capture emission. This leads to high responsivity while maintaining the low dark current.