TY - JOUR
T1 - Origins of bandgap bowing in compound-semiconductor common-cation ternary alloys
AU - Tit, Nacir
AU - Obaidat, Ihab M.
AU - Alawadhi, Hussain
PY - 2009/4/9
Y1 - 2009/4/9
N2 - We present an investigation into the existence and origins of bandgap bowing in compound-semiconductor common-cation ternary alloys. As examples, we consider CdSexTe1-x and ZnSe1-xTex alloys. A calculation, based on the sp3s* tight-binding method including spin-orbit coupling within the framework of the virtual crystal approximation, is employed to determine the bandgap energy, local density of states and atomic charge states versus composition and valence-band offset. The results show that (i)in the valence band, the top states are mainly contributed by Te atoms. The degree of ionicity of all atoms is found to vary linearly with mole fraction x. (ii)There is a strong competition between the anions (Se and Te) in trapping/losing charges and this competition is the main reason for the bandgap bowing character. (iii)There is a reasonable agreement between the calculated results and the available photoluminescence data. (iv)The bowing parameter is found to increase with increasing valence-band offset and increasing lattice mismatch.
AB - We present an investigation into the existence and origins of bandgap bowing in compound-semiconductor common-cation ternary alloys. As examples, we consider CdSexTe1-x and ZnSe1-xTex alloys. A calculation, based on the sp3s* tight-binding method including spin-orbit coupling within the framework of the virtual crystal approximation, is employed to determine the bandgap energy, local density of states and atomic charge states versus composition and valence-band offset. The results show that (i)in the valence band, the top states are mainly contributed by Te atoms. The degree of ionicity of all atoms is found to vary linearly with mole fraction x. (ii)There is a strong competition between the anions (Se and Te) in trapping/losing charges and this competition is the main reason for the bandgap bowing character. (iii)There is a reasonable agreement between the calculated results and the available photoluminescence data. (iv)The bowing parameter is found to increase with increasing valence-band offset and increasing lattice mismatch.
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U2 - 10.1088/0953-8984/21/7/075802
DO - 10.1088/0953-8984/21/7/075802
M3 - Article
C2 - 21817341
AN - SCOPUS:63749085625
SN - 0953-8984
VL - 21
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 7
M1 - 075802
ER -