Synthesis and Characterization of Heat-Tempered Cu2Zn0.6Ca0.4SnS4 Alloy Thin Film

Abstract

Six samples of Cu2Zn0.6Ca0.4SnS4 labeled Y1 – Y6 were spin-coated on a pre-cleaned glass from 20 ml each of 0.067 moll Calcium sulfate (CaSO4, 98.5% KermerR) and 0.1 mol each of zinc nitrate (Zn(NO3)2, 99% Aldrich), Copper(II)sulfate hexahydrate (Cu2SO4.6H2O, 98.5% KermerR), stannous sulfate (SnSO4, 99% KermerR), and sodium thiosulfate (Na2S2O3, 98.5% Aldrich) with ammonium hydroxide (NH4OH, 99% DHR) and triethanolamine (C6H15NO3, 99% KermerR) used as complexing agents. They were left to dry at room temperature. Y2 – Y6 were subjected to heat tempering in a carbolite furnace between 150 - 750 ℃ with a step height of 150 ℃. The alloy thin films were structurally, morphologically, and optically characterized. The grain sizes for Y1, Y2, Y3, Y4, Y5, and Y6 are 15 nm, 40nm,43 nm, 45 nm, 44 nm, and 42 nm, respectively. The interruption of the normal stacking sequence of atomic planes initially decreases as the temperature increases and the microstrain. The microstrain and stacking fault energy both climaxed at 600 ℃. Microstrain and stacking fault energy exhibit a sine and allometric relationship with the temperature (T). As the temperature increases, the band gap reduces from 3.60 eV to 3.26 eV. The residue effect of heat on the band gap variation gives a relative exponential decay of the crystallite. The difference between a shift in energy and a change in optical band gap (∆Estrain) as a function of temperature is given as -0.031 ±3.66667×10^(-4) T.