Sectional voltage contrast topography of quantum well diodes

Detailed scanning electron microscopy (SEM) of an operational quantum well laser was performed using the differential voltage contrast (DVC) method. Q uantitative measurements of Fermi energies in an operational device at high magnifications were possible due to a new calibration procedure described in this study. Precise tailoring of digitized DVC images of an operational laser taken at high and low magnifications is described. The ability to rec ord and to analyze very detailed quasi-Fermi energy (QFE) profiles across a n operational laser or transistor with 30-Angstrom features improved the DV C technique. A layered GaAs/GaxAl1-xAs/InyGa1-yAs quantum well light emitte r was tested through various operational steps, that is, inverse population , threshold, and full emission. The detailed QFE profile allowed us to anal yze collective electron behavior at various steps of operation of the laser .