TY - GEN
T1 - Comparative analysis of electronic structure evolution in Ge1-xSnx and Ge1-xPbx alloys
AU - Broderick, Christopher A.
AU - O'Halloran, Edmond J.
AU - O'Reilly, Eoin P.
N1 - Publisher Copyright:
© 2019 IEEE.
PY - 2019/7
Y1 - 2019/7
N2 - We present a comparative analysis of electronic structure evolution and the indirect- to direct-gap transition in Ge1-x(Sn,Pb)x group-IV semiconductor alloys. We present first principles disordered alloy electronic structure calculations for Ge1-x(Sn,Pb)x special quasi-random structures, and find a significantly larger band gap reduction in Ge1-xPbx than in Ge1-xSnx at fixed x. We calculate that Ge1-xPbx becomes a direct gap semiconductor close to the composition (x ≈ 7%) at which it also becomes a zero-gap semiconductor. The indirect-to direct-gap transition in Ge1-xSnx occurs over an extended composition range, also centered around 7%, and is driven by Sn-induced mixing of Ge Γ and L conduction states. The pronounced band mixing effects present in Ge1-xSnx alloys will have significant implications for optical and transport properties.
AB - We present a comparative analysis of electronic structure evolution and the indirect- to direct-gap transition in Ge1-x(Sn,Pb)x group-IV semiconductor alloys. We present first principles disordered alloy electronic structure calculations for Ge1-x(Sn,Pb)x special quasi-random structures, and find a significantly larger band gap reduction in Ge1-xPbx than in Ge1-xSnx at fixed x. We calculate that Ge1-xPbx becomes a direct gap semiconductor close to the composition (x ≈ 7%) at which it also becomes a zero-gap semiconductor. The indirect-to direct-gap transition in Ge1-xSnx occurs over an extended composition range, also centered around 7%, and is driven by Sn-induced mixing of Ge Γ and L conduction states. The pronounced band mixing effects present in Ge1-xSnx alloys will have significant implications for optical and transport properties.
UR - https://www.scopus.com/pages/publications/85071868195
U2 - 10.1109/NUSOD.2019.8806886
DO - 10.1109/NUSOD.2019.8806886
M3 - Conference proceeding
AN - SCOPUS:85071868195
T3 - Proceedings of the International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD
SP - 117
EP - 118
BT - 19th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2019
A2 - Hinzer, Karin
A2 - Piprek, Joachim
PB - IEEE Computer Society
T2 - 19th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2019
Y2 - 8 July 2019 through 12 July 2019
ER -