Development of Ar ion Beam Etching Treatment for Surface Cleaning of Cu(In1-xGax)Se2 [CIGS] Thin Films

The Ar ion beam etching treatment has been examined to develop intrinsic surface nature of Cu(In1-xGax)Se2 [CIGS] films grown in estranged systems. A low kinetic energy Ek of the irradiating ions was a key to develop an intrinsic surface. The etching with Ek > 500 eV resulted in broadening of photoemission spectra of core signals and occasional development of metallic feature around fermi energy level. These degradations were successfully suppressed by lowering Ek below 400 eV. The Cu(In1-xGax)Se2 with various x value was successfully developed and cleaned. Such as CIGS films with x=0.28 and x=1 etched with the beam of Ek = 400 eV showed a band gap of 1.27 and 1.7 eV respectively.