High pressure studies of mid-infrared type-II "W" diode lasers at cryogenic temperatures

Using high hydrostatic pressure and spontaneous emission characterisation techniques we have investigated the important loss processes in type‐II “W” diode lasers, which emit at 3.24 μm at 78 K. Our studies indicate that Auger recombination involving the excitation of holes in the valence band and/or inter‐valence‐band absorption may contribute to the temperature sensitivity of these devices, even at cryogenic temperatures. Defect/impurity related recombination, which was of concern in these structures does not appear to make a significant contribution to the threshold current over the temperature and pressure ranges investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)