Effect of structural distortion and nature of bonding on the electronic properties of defect and Li-substituted CuInSe2 chalcopyrite semiconductors

Effect of Na substitution on electronic and optical properties of CuInS2 chalcopyrite semiconductor

“…It has been established that structural distortion has prominent effects on band gap and electronic properties of pure chalcopyrite [22] and defect/substituted chalcopyrite semiconductors [23,24]. In the present work we calculate quantitative change in band gap, electronic and optical properties due to structural distortion.…”

“…Purpose is to show effects of structural distortion on electronic and optical properties. It is found LDA gives good structural properties of chalcopyrite semiconductors [22,23,24,32] and calculate accurate band gap reduction due to p-d hybridization. This is because reduction does not depend significantly on the kind of functional used [32].…”

“…[19] have reported structural, electronic and optical properties of CdGa 2 X 4 (X = S, Se, Te) using DFT based VASP code. It is well known that ternary chalcopyrites have some interesting structural anomalies [20,21,22,23,24] relative to their binary analogous. These structural anomalies have significant effects on band gap and so on overall electronic and optical properties.…”

Local Electrical Response in Alkaline-Doped Electrodeposited CuInSe2/Cu Films

“…With respect to alkaline doping, Na incorporation after deposition leads to enhanced current transport, attributed to Se vacancy passivation [5], but also to the introduction of acceptor defects, the elimination of InCu donors or the elimination of defects at grain boundaries [6]; when incorporated during growth, Na affects Cu homogeneity on a microscopic level, leading to lower charge carrier mobilities [7]. In the case of Li, a small contribution to the valence or conduction band states was found, although an increase in the band gap was attributed to effects on Se p-orbitals due to Li ionicity [8]. For K-doping in Cu(In,Ga)Se 2 , a reduced minority carrier lifetime, and poorer and temperature-dependent collection of photogenerated charge carriers were observed [6], although recent data contradict these observations [9,10]: K-doping in Cu(In,Ga)Se 2 (CIGS) films, not yet introduced during deposition or by a postdeposition treatment, increases the cell efficiency by reducing Cu at the CIGS surface upon formation of In and Ga oxides, although detrimental effects of a proposed KInSe 2 compound on the electrical properties have been mentioned in [9].…”

Local Electrical Response in Alkaline-Doped Electrodeposited CuInSe₂/Cu Films

“…With respect to alkaline doping, Na incorporation after deposition leads to enhanced current transport, attributed to Se vacancy passivation [5], but also to the introduction of acceptor defects, the elimination of InCu donors or the elimination of defects at grain boundaries [6]; when incorporated during growth, Na affects Cu homogeneity on a microscopic level, leading to lower charge carrier mobilities [7]. In the case of Li, a small contribution to the valence or conduction band states was found, although an increase in the band gap was attributed to effects on Se p-orbitals due to Li ionicity [8]. For K-doping in Cu(In,Ga)Se2, a reduced minority carrier lifetime, and poorer and temperature-dependent collection of photogenerated charge carriers were observed [6], although recent data contradict these observations [9,10]: K-doping in Cu(In,Ga)Se2 (CIGS) films, not yet introduced during deposition or by a postdeposition treatment, increases the cell efficiency by reducing Cu at the CIGS surface upon formation of In and Ga oxides, although detrimental effects of a proposed KInSe2 compound on the electrical properties have been mentioned in [9].…”