Scanning Microscopy


A series of low voltage ( < 5 keV) and low temperature ( < 20K) cathodoluminescence (CL) measurements were performed on epitaxial gallium arsenide. The purpose of these measurements was to ascertain which factors were important in furthering the development of low voltage scanning electron microscopy (LVSEM) CL. LVSEM CL potentially offers great improvement in spatial resolution and the ability to probe the optical properties of surface states. Anomalous CL effects resulting from contamination at beam voltages below 3.5 keV have been interpreted in terms of cross-over potential phenomena. Luminescence dead layers were reduced to near zero in this regime. Excitonic processes were found to be particularly sensitive to injection level and surface conditions. Very weak free-to-bound transitions persisted down to 200 eV beam voltage.

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