Optical processes and electronic states in InGaAs/GaAs V-groove quantum wire lasers

We have fabricated InGaAs/GaAs V-shaped quantum wire lasers operating with threshold in the 100 A cm -2 range at low temperature. The investigation of the electroluminescence and lasing under electrical injection and in high magnetic field elucidates the fundamental physical properties of the device. In contrast to recent claims, the emission is found to originate from free-carrier recombination independent of temperature and injection density. No excitonic lasing is found, indicating that excitons are weakly bound in these wires due to the internal piezoelectric field causing strong Stark effect.