High photoresponsivity from multilayer MoS2/Si heterojunction diodes formed by vertically stacking

Abstract

We investigated a vertically stacked p(+)-n heterojunction diode consisting of a two-dimensional (2D) molybdenum disulfide (MoS2) crystal and a heavily doped p(+)-type Si substrate. The MoS2 flakes are transferred onto p(+)-Si substrates by using a scotch tape-based exfoliation method. The performances of n-MoS2/p(+)-Si diodes are investigated by I-V measurement under light illumination using light emitting diodes with various wavelengths. It appears that multilayer MoS2 has sufficient thickness to absorb incident light from the visible to near-infrared range with a high sensitivity. With the advantages of a simple device structure as well as improved contact quality between the MoS2 and silicon interface, an ideality factor of 1.09 can be achieved. The diodes reveal an ultra-high photoresponsivity of about 980 A/W at a wavelength of 525 nm with a strong dependence on the light wavelength and intensity, while they show a high specific detectivity on the order of 10(9) cm.Hz(1/2/)W from the visible to near infrared spectral ranges.