The phase evolution of CuIn0.7Ga0.3Se2 compound powder prepared using high-energy ball milling

Abstract

We successfully prepared a homogeneous single-phase CuIn0.7Ga0.3Se2 compound powder using high-energy ball milling method. The phase evolution from initial elemental powders to intermediate metastable phases, to the final CuIn0.7Ga0.3Se2 compound at various milling stages (5 to 50min) was thoroughly investigated. The obtained powders at various stages were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe micro-analysis (EPMA) to evaluate the crystal structure, morphology, and composition of the metastable phases. The intermediate metastable phases including InSe, In2Se3, Ga2Se3, GaSe, CuSe, Cu7Se4, Cu3Se2, and CuInSe2 were formed after 5min milling. After milling for 50min, a single phase of quaternary CuIn0.7Ga0.3Se2 compound formed. The average grain size of the milled powder was about 9.3nm. The results of EPMA also confirmed that a homogeneous CuIn0.7Ga0.3Se2 alloy was formed.