Correlation between interface modification and rectifying behavior of p-type Cu2ZnSnS4/n-type Si diodes

The effect of surface sulfidation of Si on electronic transport of heterojunction diodes based on the p-type Cu2ZnSnS4 (CZTS) and n-type Si is investigated. The temperature-dependent current-voltage (I-V) characteristics of CZTS/Si diodes with and without sulfide treatment are measured in the temperature range of -30 90 A degrees C. The temperature dependence of forward bias I-V characteristics can be explained on the basis of the thermionic emission theory. Compared with the CZTS/Si diode without sulfide treatment, the CZTS/Si diode with sulfide treatment exhibits a better rectifying behavior. The enhanced device performance is mainly the result of the formation of Si-S bonds that serve to reduce the interfacial potential fluctuations. In order to obtain a greater understanding of the improved rectifying I-V characteristics, the photoresponse measurement is performed. The increased photocurrent density can be interpreted by the device rectifying performance and interface passivation.