Fabrication and Characterization of Cu2ZnSnSe4 Thin-Film Solar Cells using a Single-Stage Co-Evaporation Method: Effects of Film Growth Temperatures on Device Performances

Abstract

Kesterite-structured Cu2ZnSnSe4 (CZTSe) is considered as one of the Earth-abundant and non-toxic photovoltaic materials. CZTSe films have been prepared using a single-step co-evaporation method at a relatively low temperature (i.e., below 500 °C). Due to the volatile nature of tin-selenide, the control over substrate temperature (i.e., growth temperature) is very important in terms of the deposition of high-quality CZTSe films. In this regard, the effects of growth temperatures on the CZTSe film morphology were investigated. The suitable temperature range to deposit CZTSe films with Cu-poor and Zn-rich compositions was 380–480 °C. As the temperature increased, the surface roughness of the CZTSe film decreased, which could improve p/n junction properties and associated device performances. Particularly, according to capacitance-voltage (C-V) and derived-level capacitance profiling (DLCP) measurements, the density of interfacial defects of CZTSe film grown at 480 °C showed the lowest value, of the order of ~3 × 1015 cm−3. Regardless of applied growth temperatures, the formation of a MoSe2 layer was rarely observed, since the growth temperature was not high enough to have a reaction between Mo back contact layers and CZTSe absorber layers. As a result, the photovoltaic (PV) device with CZTSe film grown at 480 °C yielded the best power conversion efficiency of 6.47%. It is evident that the control over film growth temperature is a critical factor for obtaining high-quality CZTSe film prepared by one-step process.

Mechanism‐Based Approach of CdS/Cu(In,Ga)Se2 (CIGS) Interfaces for CIGS Solar Cells through Deposition in Different Stages of Continuous Chemical Bath Deposition Reaction: Key to Achieving High Photovoltaic Performance

“…In solar cell research, compound thin films, such as Cu(In,Ga) Se 2 (CIGS), Cu 2 (Zn,Sn)Se 4 (CZTS), Cu 2 SnS 3 (CTS), CuSbS 2 (CAS), and others, [1][2][3][4][5][6][7][8][9][10][11] have been studied as alternative absorbers to commercially produced crystalline Si solar cells. As absorbers, compound thin films only need to be 1-2 μm thick due to their high absorption coefficients compared to the 100-300 μm thick crystalline Si.…”

Defect Engineering in Earth‐Abundant Cu2ZnSnSe4 Absorber Using Efficient Alkali Doping for Flexible and Tandem Solar Cell Applications

“…However, the co‐evaporation process with Cu, Zn, Sn, and Se elemental sources is simple and enables the growth of high‐quality films at temperatures lower than 500 °C. [ 12 ] Furthermore, alkali post‐deposition treatment (PDT) is applied to the same batch. Using this method, National Renewable Energy Laboratory (NREL) reported the highest efficiency, 9.15%, for a Cu 2 ZnSnSe 4 (CZTSe) solar cell with an e‐beam‐evaporated NaF precursor on a Mo/glass substrate.…”

Effect of Zn(S,O,OH) Buffer Thin Films Formed on CIGS through Different Stages and Reaction Processes in Chemical Bath Deposition: Interpretations from Mechanisms and Transformation Kinetics Perspective

“…Compound thin films require buffer materials to form solar cells with reduced lattice mismatch and smooth bandgaps (E g ) for charge transfer. Among the compound thin films, such as Cu(In,Ga)Se 2 (CIGS), [1][2][3][4][5][6] Cu 2 (Zn,Sn)Se 4 (CZTS), [7] CuSbS 2 (CAS), [8][9][10][11] Cu 2 SnS 3 (CTS), [12] and others, [13,14] CIGS shows the highest efficiency as a solar cell absorber. Most CIGS solar cells have traditionally used CdS as a buffer material.…”