Temperature dependence of Raman scattering in the Cu2ZnSnSe4 thin films on a Ta foil substrate

A.V Stanchik,M.S Tivanov,I.I Tyukhov,R Juskenas,O.V Korolik,V.F Gremenok,A.M Saad,A Naujokaitis

doi:10.1016/j.solener.2020.03.043

A.V Stanchik, M.S Tivanov + Show 6 more

Open Access

https://doi.org/10.1016/j.solener.2020.03.043

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Abstract

The temperature dependence (in range from 24 to 290 K) of Raman spectroscopy of the Cu2ZnSnSe4 (CZTSe) films with Zn-rich (series A) and Zn-poor (series B) composition obtained on a Ta foil is investigated. Analisys and approximation by the Lorentz function of the CZTSe Raman spectra suggests that the CZTSe most intense Raman peak consists of two modes (at 192/189 and 194/195 cm−1), which are slightly shifted from each other. In addition, the Raman peaks around 192 and 189 cm−1 lead to asymmetric broadening of dominant peaks at 194 and 195 cm−1 in Raman spectra of the CZTSe films series A and B, respectively. In the case of the Sn-rich CZTSe films, we attribute of Raman peak around 189 cm−1 to SnSe2 compound. However in the case of the Sn-poor CZTSe films, the observable shift is too high to assign confidently the 192 cm−1 band to a SnSe2 compound, which was not detected by XRD analysis. We suppose that this mode is attributed to disordered kesterite structure. The temperature dependence Raman spectra for both series of the CZTSe films shows that a change temperature from 290 to 24 K leads to position shift and narrowing of the CZTSe Raman A-modes. The calculated temperature coefficients and anharmonic constants in Klemens model approximations for temperature dependence of shift position and FWHM of the CZTSe A-modes shown that four-phonon process has dominant contribution in damping process and as a consequence in Raman spectrum changes for two series of the CZTSe films.

Highlights

Semiconductor thin films obtained on flexible metal substrates have been of great interest for use in solar cells (Salavei et al, 2016; Chantana et al, 2018; Sim et al, 2018; Zhao et al, 2018; Yan et al, 2019)
The existence of ZnSe phase in the both CZTSe films was confirmed by Raman spectroscopy
The SnSe2 phase was detected in the CZTSe films series B using the X-ray and Raman spectroscopy

Summary

Introduction

Semiconductor thin films obtained on flexible metal substrates have been of great interest for use in solar cells (Salavei et al, 2016; Chantana et al, 2018; Sim et al, 2018; Zhao et al, 2018; Yan et al, 2019). Raman spectroscopy provides information regarding optical modes of vibrations due to inelastic light scattering This method is a unique technique to study the temperature behaviour of materials (Wu et al, 2008), for example, thermal conductivity, as thermal and electrical properties of the semiconductor thin films are affected by anharmonic phonon-phonon interactions. The temperature dependence of the Raman peaks position and FWHM for CZTSe films obtained on a flexible Ta substrate was investigated in the temperature range of 24–290 K These analyses are essential for understanding the structural properties and phononic behaviors of this absorbers obtained on metal substrates. At the present time, there are no experimental works to determine and analyze anharmonic phonon properties of the CZTSe films using Raman spectroscopy

Synthesis of the CZTSe thin films

Characterization

Composition and morphology

Raman spectroscopy

Temperature dependence of Raman shift and linewidth

Conclusions