Investigation of structural and surface potential studies of CZTS nanorods

Abstract

Copper zinc tin sulphide (Cu2ZnSnS4) known as CZTS is a potential absorber layer due to its non toxicity and earth abundant availability of its constituent elements. CZTS nanorods are successfully synthesized using hydrothermal route and characterized by X-ray powder diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, raman spectroscopy, and Kelvin probe force microscopy (KPFM) techniques. XRD and Raman it confirm that the synthesized CZTS samples are in keseterite phase without any impurities. From FESEM and EDAX, the elemental ratio is observed to 1.81:0.90:0.85:3.71. Raman study shows the peak position at 287, 339, and 372 cm−1 which corresponds to CZTS pure phase without any impurity peak. Surface potential and work function of CZTS nanorods (NRs) has been derived by KPFM data. KPFM shows that with an increase in diameter of CZTS nanorods surface potential decreases indicating enhancement of p-type conductivity with decrease in NR diameter. The value of surface potential is found to be 496 and 486 mV NRs with diameter 40 and 60 nm, respectively. The results are explained on the basis of Oxygen induced passivation of surface states in NRs diameter. The results of the study are important for potential applications of CZTS NRs in the field of optoelectronic and solar cells.