Cu2ZnSnS4 absorption layers with controlled phase purity

Abstract

We report the synthesis and characterization of Cu2ZnSnS4 (CZTS) with controlled phase purity. The precursor was first prepared using sequential electrodeposition of Cu, Zn, and Sn in different orders. The Cu/(Sn+Zn) ratio in each stacking order was also varied. The precursor was subjected to annealing at 200°C and sulfurization at 500°C in a 5%-H2S/Ar atmosphere for the formation of CZTS. The phase evolutions during the electrodeposition and annealing stages, and the final phase formation at the sulfurization stage were examined using both x-ray diffractometry and Raman spectroscopy, both of which are shown to be complimentary tools for phase identification. Detailed growth path is therefore reported. We also demonstrate by controlling the stacking order and the Cu/(Sn+Zn) ratio, CZTS with a phase purity as high as 93% is obtained.

Polarized Raman scattering study of kesterite type Cu2ZnSnS4 single crystals

“…The Cu 2 ZnSnS 4 (CZTS) quaternary compound is widely discussed over the last few years as an active layer in thin films photovoltaic devices1234567891011. Although the electronic properties of the CZTS-heterojunction solar cells have been studied extensively the knowledge of the CZTS basic properties is still limited.…”

Impact of sulphurization environment on formation of $$\hbox {Cu}_{2}\hbox {ZnSnS}_{4}$$ Cu 2 ZnSnS 4 films using electron beam evaporated stacked metallic precursors

“…CZTS films can be prepared by vacuum-based methods like electron beam evaporation [7], sputtering [8] etc., and non-vacuum techniques like dip coating [9,10], spin coating [11], electrodeposition [12] etc. Among the vacuum-based techniques, CZTS films can be prepared by (i) sulphurization of the metallic precursors deposited sequentially [13][14][15], (ii) deposition of metallic sulphide precursor films and annealing in an inert environment [16,17] and (iii) deposition using a quaternary CZTS target [5,18,19].…”

“…Su et al [15] fabricated CZTS films through sequential electrodeposition of metallic precursors and observed that the compositional ratio and stacking order have a major role in CZTS phase formation and they successfully prepared a 93% phase pure CZTS film with a glass/Zn/Sn/Cu precursor stack. Recent studies from Thota et al [20] and Olgar et al [21] also reveal that films having a Cu layer adjacent to both Sn and Zn layers have enhanced performance as an absorber layer due to the uniform diffusion of the precursor layers while annealing.…”

“…In the case of CZTS films prepared through sequential deposition of metallic precursors, sulphurization of the films can be done either in the presence of elemental S powder or H 2 S gas [5,14,15,22]. By optimizing the precursor stacking sequence, sulphurization ramping rate and environment, formation of impurity phases can be reduced effectively.…”

Influence of Cu 2 S, SnS and Cu 2 ZnSnSe 4 on optical properties of Cu 2 ZnSnS 4

“…Some examples are Cu 2 S and SnS 2 (see, e.g., Refs. [6,[14][15]) with band gaps of 1.2-1.8 eV [15] and ~2.2 eV [16], respectively, that can be formed in CZTS at annealing temperatures T≥350 °C. Band gap of SnS is ~1.32 eV [17], so the SnSbased secondary phases might play important role in electro-optical properties of CZTS.…”