Direct-band-gap absorption in germanium under pressure
1989; American Physical Society; Volume: 39; Issue: 17 Linguagem: Inglês
10.1103/physrevb.39.12921
ISSN1095-3795
AutoresA.R. Go�i, K. Syassen, M. Cardona,
Tópico(s)Nanowire Synthesis and Applications
ResumoThe optical absorption of Ge near the direct band gap ${E}_{0}$ (${\ensuremath{\Gamma}}_{8v}^{+}$\ensuremath{\rightarrow}${\ensuremath{\Gamma}}_{7c}^{\mathrm{\ensuremath{-}}}$) has been investigated at pressures up to 9 GPa with use of thin samples of 3 and 11 \ensuremath{\mu}m thickness. We find a linear blue shift of the gap energy (${\mathrm{dE}}_{0}$/dP=0.121 eV/GPa) and an indication for a small increase of the corresponding spin-orbit splitting ${\ensuremath{\Delta}}_{0}$ by 2.4 meV/GPa. The pressure dependence of the band gap ${E}_{0}$ predicted by recent ab initio band-structure calculations is in good agreement with the present experimental results. The strength of the absorption at the direct edge is found to increase by a factor of 3 in the pressure range from 0 to 9 GPa.
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