Formation Mechanisms of Cu(In _0.7 Ga _0.3 )Se ₂ Nanocrystallites Synthesized Using Hot‐Injection and Heating‐Up Processes

Abstract

Nearly monodispersed CuIn 0.7 Ga 0.3 Se 2 (CIGS) nanocrystals were successfully prepared using the thermal decomposition of copper, indium (In), gallium (Ga), and selenium–oleylamine (OLA) complexes via the heating‐up process. The phase formation sequence was CuSe→CuInSe 2 →CIGS. The CIGS nanocrystals synthesized using the heating‐up process exhibited a single chalcopyrite phase and its chemical composition was close to stoichiometric. However, phase separation of the In‐rich and Ga‐rich phases was found using the hot‐injection method due to the difference in reactivity between In–OLA and Ga–OLA complexes.