Wurtzite silicon as a potential absorber in photovoltaics: Tailoring the optical absorption by applying strain

Wurtzite silicon as a potential absorber in photovoltaics : Tailoring the optical absorption by applying strain

QC 20150818
We present ab initio calculations of the electronic structure and the optical properties of wurtzite Si (Si-IV). We find an indirect band gap of 0.95 eV (Gamma(5) -> M-1) and an optically forbidden direct gap of 1.63 eV (Gamma(5) -> Gamma(10)), which is due to a backfolding of the L-1 state of Si in the diamond structure (Si-I). Optical absorption spectra including excitonic and local-field effects are calculated. Further, the effects of hydrostatic pressure, uniaxial strain, and biaxial strain on the absorption properties are investigated. Biaxial tensile strains enhance the optical absorption of Si-IV in the spectral range which is relevant for photovoltaic applications. High biaxial tensile strains (>4%) even transform Si-IV into a direct semiconductor.

Sander, T. (författare)
Bechstedt, F. (författare)
Vidal, J. (författare)
Olsson, PärKTH,Reaktorfysik,CNRS, Chim ParisTech, France(Swepub:kth)u1wo7ztz (författare)
Laribi, S. (författare)
Guillemoles, J. -F (författare)
KTHReaktorfysik (creator_code:org_t)

Ingår i:Physical Review B. Condensed Matter and Materials Physics92:41098-01211550-235X

Av författaren/redakt...: Roedl, C.; Sander, T.; Bechstedt, F.; Vidal, J.; Olsson, Pär; Laribi, S.; visa fler...; Guillemoles, J. ...; visa färre...

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