Title :
Band-gap engineering in Cu(In,Ga)Se2 thin films grown from (In,Ga)2Se3 precursors
Author :
Gabor, Andrew M. ; Tuttle, John R. ; Schwartzlander, Amy ; Tennant, Andrew L. ; Contreras, Miguel A. ; Noufi, Rommel
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
A three-stage process starting with the deposition of (In,Ga)2Se3 precursor films has been successful in the fabrication of graded band-gap Cu(In,Ga)Se2 thin films. In this work we examine (1) the reaction of Cu+Se with (In,Ga)2 Se3, which leads to a spontaneous grading in the Ga content as a function of depth through the film, and (2) modification of the Ga content in the surface region of the film through a final deposition of In+Ga+Se. We show how band-gap grading can be enhanced by the formation of nonuniform precursors, how counterdiffusion limits the degree of grading possible in the surface region, and how the Cux Se secondary phase acts to homogenize the film composition
Keywords :
CVD coatings; copper compounds; energy gap; indium compounds; semiconductor growth; semiconductor thin films; solar cells; ternary semiconductors; (In,Ga)2Se3 precursors; (InGa)2Se3; Cu(In,Ga)Se2 thin film growth; Cu(InGa)Se2; Cu+Se reaction; CuxSe secondary phase; CuSe; Ga content grading; band-gap engineering; counterdiffusion; film composition homogenisation; graded band-gap; nonuniform precursors; solar cells; surface region; Electron emission; Photonic band gap; Photovoltaic cells; Protection; Region 6; Substrates; Surface morphology; Thermionic emission; Transistors; Zinc oxide;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.519813
