Synthesis of a new Cu2MgGeS4 quaternary compound thin film by a low-cost spray method: Structural, Raman and optical properties

Abstract

• Cu 2 MgGeS 4 thin film was synthesized for the first time. • Tetragonal kesterite structure was confirmed. • Raman measurement was conducted for the first time for Cu 2 MgGeS 4. • An optical band gap of 1.80 eV was obtained. In this work, the new Cu 2 MgGeS 4 quaternary compound thin film was synthesized for the first time by spray-ultrasonic of Cu–Mg–Ge precursors onto glass-substrate followed by a sulfurization for 1 h at 500 °C. The EDX Mapping shows a uniform desitribution of Cu–Mg–Ge–S with a value near to the ideal stoichiometry of 2:1:1:4 of Cu 2 MgGeS 4 . X-ray diffraction displaying typical peaks relating to (1 1 2), (0 0 4), (1 0 5), (2 2 0) and (3 1 2)/(1 1 6) planes of the tetragonal kesterite Cu 2 MgGeS 4 phase ( I 4 ¯ ), the result was confirmed by the presence of all characteristic Raman peak of kesterite structure, especially the predominant peak at (361 cm −1 ). The optical-gap is around 1.80 eV with a high absorption in the visible solar range. These achievements make this new material a potential candidate for solar conversion applications.