The mechanical strain and the defect concentration in AlGaAs–GaAs-based high-power diode laser arrays were monitored. This permitted study of the interplay between these extrinsic parameters as a function of device operation. There were 2 parameters which contributed to the spread of the mechanical strain: the local position at the device, and the device operation time that substantially enhanced the strain. For mid-gap levels as well as shallower defect levels, which were due to physically different defects, very different creation scenarios were observed. The concentration of shallow defects and band-tail states was strongly correlated with compressive strains in their vicinity, no matter how the strain was created. For mid-gap levels, there was no direct correlation. However, an increase by a factor of 3 after 1500h of operation time was observed. The knowledge of defect creation scenarios could be extrapolated to other GaAs-based devices.

Mechanical Strain and Defect Distributions in GaAs-Based Diode Lasers Monitored during Operation. T.Q.Tien, J.W.Tomm, M.Oudart, J.Nagle: Applied Physics Letters, 2005, 86[11], 111908 (3pp)