Effects of the metallic target compositions on the absorber properties and the performance of Cu2ZnSnSe4 solar cell devices fabricated on TiN-coated Mo/glass substrates

Cu2ZnSnSe4 (CZTSe) films have been fabricated by sputtering of Cu–Zn–Sn metallic targets on the TiN-coated Mo/glass substrates, followed by selenization at 500–600 °C for 1 h under a compensation disk. Three targets of A, B, and C, with different ratios of Cu, Zn, and Sn elements were fabricated by hot pressing the constitutive powder mixture. The effects of the targetʹs compositions on the growth behavior, microstructural characteristics, and electrical properties of CZTSe films have been investigated. Influence of the targetʹs composition outshined the CZTSe films in grain growth, film composition, electrical properties, and solar cell performance. The CZTSe films deposited from target B of [Cu]/[Zn]/[Sn] at 2/1/1 had a [Cu]/([Zn] + [Sn]) ratio of 1.01, large grains of 2.5–5.0 μm, and high mobility of ∼80 cm2 V−1 s−1 and its fabricated solar cell device had the efficiency of 2.6%, as compared to the TiN-free device with 0.58% efficiency.