Cathodoluminescence system for a scanning electron microscope using an optical fiber for light collection

Abstract

We describe a novel light collection system for cathodoluminescence scanning electron microscopy. Cathodoluminescence emitted from the sample surface enters directly into the facet of an optical fiber, which is held less than a millimeter away from the sample to optimize the collection efficiency. The fiber is small enough that it has a minimal effect on access to the sample by other detection apparatus. Three axis positioning of the fiber is accomplished with motorized translation stages located in the sample chamber. Techniques for generating cathodoluminescence images and local spectra are discussed. The techniques are applied to oval defects in molecular beam epitaxially grown GaAs/AlGaAs epilayers, and the results are presented.