Structural properties of Cu(In,Ga)Se 2 thin films prepared from chemically processed precursor layers

• Published in: Thin solid films Vol. 517; no. 7; pp. 2235 - 2239
• Main Authors: Hibberd, C.J., Ganchev, M., Kaelin, M., Dann, S.E., Bilger, G., Upadhyaya, H.U., Tiwari, A.N.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02.02.2009
• Subjects: CIGS; CuInGaSe 2; Ion exchange; Non vacuum; Thin film solar cells; Ion exchange; CuInGaSe 2; CIGS; Non vacuum; Thin film solar cells
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2008.10.094

We have developed a chemical process for incorporating copper into indium gallium selenide layers with the goal of creating a precursor structure for the formation of copper indium gallium diselenide (CIGS) photovoltaic absorbers. Stylus profilometry, EDX, Raman spectroscopy, XRD and SIMS measurements show that when indium gallium selenide layers are immersed in a hot copper chloride solution, copper is incorporated as copper selenide with no increase in the thickness of the layers. Further measurements show that annealing this precursor structure in the presence of selenium results in the formation of CIGS and that the supply of selenium during the annealing process has a strong effect on the morphology and preferred orientation of these layers. When the supply of Se during annealing begins only once the substrate temperature reaches ≈ 400 °C, the resulting CIGS layers are smoother and have more pronounced preferred orientation than when Se is supplied throughout the entire annealing process.