Cathodoluminescence imaging and spectroscopy by near-field detection

Using near-field techniques, we have developed an experimental set-up for s patially resolved cathodoluminescence (CL) spectroscopy and monochromatic i maging. It combines a scanning near-field optical/force microscope with a s canning electron microscope equipped with a field emission gun. The potenti alities of this scanning near-field cathodoluminescence microscope are demo nstrated on two kinds of sample: an indented MgO crystal and AlGaN/GaN quan tum wells grown on GaN/sapphire. Monochromatic CL imaging allows a clear di stinction between the emission of quantum wells and the GaN substrate, and for the MgO crystal, the localization on the slip bands, near the indentati on, of luminescent centres emitting at 450 nm.