Optical-luminescence

Luminescence optical spectroscopy is a classical spectroscopy to characterize excited states in semiconductors. It is based on an optical excitation with an excess energy with respect to the band gap. The various pathways of de-excitation give rise to a re-emitted photon distribution with energy related to the excited states.

The lineshape as a function of the re-emitted photon energy is generally modeled by the product of the absorption times the photoexcited electron and hole distribution functions at energies coupled by the photon. In this approximation a common temperature of electrons and holes is postulated and by fitting the high energy tail of the spectrum the carriers temperature can be retrieved.

The PhotoLumiscence also provides a scenario for the exciton dynamics; in particular, varying the flux of the photon beam, the PhotoLuminescence intensity is super-linear in the case of exciton-exciton interaction.

Moreover, PhotoLuminescence at low temperature is a powerful tool to characterize point defects in semiconductors, and it is a fundamental characterization to improve the quality of the semiconductors in electronic devices.