Effects of Sulfurization Pressure on the Conversion Efficiency of Cosputtered Cu₂ZnSnS₄Thin Film Solar Cells

Abstract

We report herein Cu 2 ZnSnS 4 (CZTS) thin film solar cells with 6.75% conversion efficiency, without an antireflection coating. The CZTS precursors have been prepared by cosputtering using three different targets on Mo-coated substrates: copper (Cu), tin sulfide (SnS), and zinc (Zn). The postsulfurization was carried out at different pressures in a H 2 S/N 2 environment at 550 ∘ C for one hour. A comparative study on the performances of solar cells with CZTS absorber layers prepared at different sulfurization pressures was carried out. The device efficiency of 1.67% using CZTS absorber and low pressure sulfurization is drastically improved, to an efficiency of 6.75% with atmospheric pressure sulfurization.

Importance of CdS buffer layer thickness on Cu2ZnSnS4-based solar cell efficiency

“…These images show that some of the CZTS layers, used for device fabrications, include void formations. In the CZTS literature, it is often reported that the voids at the Mo-CZTS interface, which are called Kirkendall voids, form due to the different interdiffusion velocities of Cu, Zn, and Sn elements [58,59]. From the SEM cross sections of devices shown in figure 11, the thicknesses of CdS buffer layers deposited for 90, 75, 60 and 45 min were measured as 140.0, 134.9, 102.5, and 75.5 nm for cells 1 to 4, respectively.…”