Photoluminescence and Photoreflectance

As a result of rapid development in semiconductor manufacturing, many types of optoelectronic devices such as laser diodes, LEDs, and high-electron-mobility transistors (HEMTs) are now fabricated by epitaxial-growth methods. To improve and characterize their quality, these devices are optically inspected. Photoluminescence (PL) and photoreflectance (PR) spectroscopy are among the most important optical methods. PL and PR are contactless, non-destructive techniques, and different kinds of optical information can be acquired from each. PL studies photons emitted from a material or device when excited by an external light source.