TY - JOUR
T1 - Texture and morphology variations in (In,Ga)2Se3 and Cu(In,Ga)Se2 thin films grown with various Se source conditions
AU - Ishizuka, Shogo
AU - Yamada, Akimasa
AU - Fons, Paul
AU - Niki, Shigeru
N1 - Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/6
Y1 - 2013/6
N2 - Texture and morphology variations in co-evaporated (In,Ga) 2Se3 and Cu(In,Ga)Se2 (CIGS) films grown with various Se source conditions during growth were studied. The Se species of simply evaporated, large molecular Se (E-Se, low-sticking coefficient), and RF-plasma cracked atomic Se (R-Se, high sticking coefficient) were used in the present work. (In,Ga)2Se3 precursor films, which were prepared during the first stage of CIGS film growth by the three-stage process, showed systematic variations in texture and Na distribution profile with varying evaporative Se (E-Se) flux. The properties of CIGS films and solar cells also showed systematic variations, and the open-circuit voltage (Voc) and fill factor were found to be especially sensitive to the E-Se flux. R-Se grown (In,Ga)2Se3 precursor films featured granular morphology with strong (105) and (301) peaks in the diffraction pattern, and the texture was very similar to an E-Se grown film fabricated with a Se to group III metal (In + Ga) flux ratio (P[Se]/[In + Ga]) of about 6, although the nominal P[Se]/[In + Ga] used for an R-Se source was very small and less than 0.5. The R-Se grown CIGS films displayed, however, highly dense surfaces and larger grain sizes than E-Se grown CIGS films. The controllability of film morphology and the Na diffusion profile in (In,Ga)2Se 3 and CIGS films with various Se source conditions are discussed.
AB - Texture and morphology variations in co-evaporated (In,Ga) 2Se3 and Cu(In,Ga)Se2 (CIGS) films grown with various Se source conditions during growth were studied. The Se species of simply evaporated, large molecular Se (E-Se, low-sticking coefficient), and RF-plasma cracked atomic Se (R-Se, high sticking coefficient) were used in the present work. (In,Ga)2Se3 precursor films, which were prepared during the first stage of CIGS film growth by the three-stage process, showed systematic variations in texture and Na distribution profile with varying evaporative Se (E-Se) flux. The properties of CIGS films and solar cells also showed systematic variations, and the open-circuit voltage (Voc) and fill factor were found to be especially sensitive to the E-Se flux. R-Se grown (In,Ga)2Se3 precursor films featured granular morphology with strong (105) and (301) peaks in the diffraction pattern, and the texture was very similar to an E-Se grown film fabricated with a Se to group III metal (In + Ga) flux ratio (P[Se]/[In + Ga]) of about 6, although the nominal P[Se]/[In + Ga] used for an R-Se source was very small and less than 0.5. The R-Se grown CIGS films displayed, however, highly dense surfaces and larger grain sizes than E-Se grown CIGS films. The controllability of film morphology and the Na diffusion profile in (In,Ga)2Se 3 and CIGS films with various Se source conditions are discussed.
KW - (In,Ga)Se
KW - Cu(In,Ga)Se
KW - RF-plasma cracked Se
KW - Se flux
KW - texture
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U2 - 10.1002/pip.1227
DO - 10.1002/pip.1227
M3 - Article
AN - SCOPUS:84878189897
VL - 21
SP - 544
EP - 553
JO - Progress in Photovoltaics: Research and Applications
JF - Progress in Photovoltaics: Research and Applications
SN - 1062-7995
IS - 4
ER -