Cross-sectional scanning tunneling microscopy (STM) has been used to study in-operation changes that occur at the active region of clean-cleaved semiconductor laser diodes. A tunneling model that allows the inclusion of tip-induced band bending and surface defect states has been used to study the origin of the surface changes which give rise to the observed modification. Low-doped layers close to the active region are found to undergo both a reduction in doping concentration and an increase in the surface defect state density as the lasers are operated. These changes ultimately lead to device failure. Under different tunneling modes STM can be sensitive to one effect or the other, and the importance of modeling the changes to confirm which are occurring is emphasized.
ASJC Scopus subject areas
- Physics and Astronomy(all)