Investigating inter-well dopant concentration variations in doped MQWs with 20nm spatial resolution using SEM-CL

Si-doped GaAs quantum wells are examined in cross-section using SEM-based cathodoluminescence. Spatial resolution of just 20nm is demonstrated, representing a three-fold improvement over previously demonstrated resolution in this technique. Nominally identical doped wells are observed to give strongly differing intensities of cathodoluminescence. The possible reasons for this are discussed.