Cross-sectional photoluminescence and its application to buried-layer semiconductor structures

We present an overview of a cross-sectional scanning microphotoluminescence technique that is used to examine various buried-layer semiconductor structures for which traditional surface-normal techniques cannot yield sufficient information or must be coupled with time-consuming and painstaking processes such as wet etching. This technique has a wide range of applications; two—defect-driven interdiffusion in quantum wells and the modification of spontaneous emission from quantum wells in vertical-cavity surface-emitting lasers (VCSELs)—are discussed here. The data obtained using this method can be used to distinguish emission spectra from quantum wells as little as one micrometer apart in depth and a few nanometers different in wavelength. The comparison of normal incidence with cross-sectional data from VCSELs can be used to more effectively optimize the match between cavity resonance and quantum well emission in high-Q devices.