Spatiotemporally Resolved Optical Measurements on Photocarrier Dynamics in Copper Monosulfide

In this paper, we report a transient absorption microscopy study of photocarrier dynamics in CuS crystals at room temperature. The photocarriers are injected into the sample by interband absorption of a 410 nm pump pulse and are detected by measuring the differential reflection of a 660 nm probe pulse as a function of both the time delay and the spatial position of the probe pulse. By analyzing the spatiotemporal dynamics of these carriers, we obtained a diffusion coefficient of 4.4 +/- 0.5 cm(2) s(-1), which corresponds to a mobility of 163 cm(2) V-1 s(-1). The moderate photocarrier transport performance indicates potential optoelectronic applications of CuS as a semiconducting material. Our results also illustrate the prospects of fabricating two-dimensional materials and heterostructures with CuS.