Transverse magnetic and transverse electric polarized inter-subband absorption and photoconductivity in p-type SiGe quantum wells

We have investigated the polarization dependence of subband absorption and photoconductivity in Si/SiGe quantum wells. For samples with a hole concentration of ps=2.8×1012 cm−2 both transverse magnetic and transverse electric polarized absorptions have been observed, and transitions to several excited states are clearly identified by comparison with self-consistent Luttinger–Kohn type calculations. The photoconductivity is surprisingly little sensitive to the polarization, which indicates the importance of the subsequent transport process on the photocurrent responsivity.