Effect of Annealing on Physical Properties of Cu2ZnSnS4 (CZTS) Thin Films for Solar Cell Applications

Subject Areas : Journal of Optoelectronical Nanostructures

Heydar Izadneshan ¹ , Ghahraman Solookinejad ²

1 - Department of physics, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.
2 - Department of physics, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.

Received: 2018-01-16 Accepted : 2018-06-17 Published : 2018-06-01

Keywords: Solar Cells, Optical Properties, CZTS, Magnetron Sputtering,

Abstract :

Cu2ZnSnS4 (CZTS) thin films were prepared by directly sputtering
Cu (In,Ga)Se2 quaternary target consisting of (Cu: 25%, Zn: 12.5%, Sn; 12.5%
and S: 50%). The composition and structure of CZTS layers have been
investigated after annealing at 200 0C, 350 0C and 500 0C under vacuum. The
results show that recrystallization of the CZTS thin film occurs and increasing
the grain size with a preferred orientation in the (112) direction was obtained. The
Raman spectra showed the existence of crystalline CZTS phase after annealing.
Optical transmission spectra were recorded within the range 300-900 nm. The
energy band gap (Eg) of the CZTS thin films was calculated before and after
annealing from the transmittance spectra using Beer-Lambert’s law. Results show
that Eg is dependent on the annealing temperature. The optical band gap of CZTS
also varied from 1.57 eV to 1.31 eV with increase in the annealing temperature
from 200 0C min to 500 0C.

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