Temperature dependent polarization switching and band gap anomalies in strained GaInAs quantum wire heterostructures

摘要

[[abstract]]We report on the polarized photoluminescence (PPL) properties of strained GaxIn1−xAs quantum wire (QWR) heterostructures formed in situ by the strain-induced lateral-layer ordering process. It is found that the PPL spectra of these QWRs have unique properties that depend on temperature and orientation of the pump polarization with respect to the QWR direction. In particular, the dominant polarization switches when the sample is warmed from 77 to 300 K provided the pump polarization is parallel to the QWRs. This indicates that the light-hole (LH) and heavy-hole (HH) bands cross with increasing temperature, which implies that the multiaxial strain in this material is a function of temperature. Furthermore, this effect is only observed in GaxIn1−xAs QWR heterostructures that display anomalous band-gap stability with respect to temperature. It is believed that the strain induced temperature dependent LH–HH crossing as evidenced by the polarization switching switching effect is responsible for this anomaly.