Editing Scanning electron microscope (section)

==Beam-injection analysis of semiconductors==
The nature of the SEM's probe, energetic electrons, makes it uniquely suited to examining the optical and electronic properties of semiconductor materials. The high-energy electrons from the SEM beam will inject [[charge carrier]]s into the semiconductor. Thus, beam electrons lose energy by promoting electrons from the [[valence band]] into the [[conduction band]], leaving behind [[electron hole|holes]].

In a [[direct bandgap]] material, recombination of these electron-hole pairs will result in cathodoluminescence; if the sample contains an internal electric field, such as is present at a [[p-n junction]], the SEM beam injection of carriers will cause [[electron beam induced current]] (EBIC) to flow. Cathodoluminescence and EBIC are referred to as "beam-injection" techniques, and are very powerful probes of the optoelectronic behavior of semiconductors, in particular for studying nanoscale features and defects.