Another route to fabricate single-phase chalcogenides by post-selenization of Cu-In-Ga precursors sputter deposited from a single ternary target

Single-layered precursors comprising In and Cu(11)(In,Ga)(9) were fabricated by one-step sputtering of a Cu-In-Ga ternary target, subsequently covered by an evaporated Se layer as the source of post-selenization, involving low-temperature (100 degrees C) homogenization and high-temperature (>= 450 degrees C) chalcogenization treatments. Initially it appears that the post-selenization process is inappropriate to fabricate device-quality CIGS absorber layers because the composite precursor is converted into (In,Ga)(2)Se(3) and Cu(3)Se(2) with segregated phases and roughened topography. However, adequately controlling the processing steps leads to a fully microstructure-homogenized precursor, offering a new route and chemical reaction process to fabricate Cu(In,Ga)Se (CIGS) absorber layer with sounding crystallinity. (C) 2009 Elsevier B.V. All rights reserved.