Mechanical strain and defect distributions in GaAs-based diode lasers monitored during operation (original) (raw)

We monitor the mechanical strain and the defect concentration in AlGaAs-GaAs-based high-power diode laser arrays. This allows studying the interplay between these extrinsic parameters in dependence on device operation. There are two parameters, which contribute to the spread of the mechanical strain, the local position at the device, and, the device operation time that substantially enhances the strain. For midgap levels as well as shallower defect levels, which are due to physically different defects, very different creation scenarios are observed. The concentration of shallow defects and band-tail states is strongly correlated with compressive strain in their vicinity, no matter how the strain is created. For midgap levels, there is no direct correlation; however, an increase by a factor of 3 after 1500 h of operation time is observed. The knowledge on defect creation scenarios is extensible to other GaAs-based devices.