<title>Characterization Of Semiconductors By Photoluminescence And Photoluminescence Excitation Spectroscopy</title>

Abstract

A tutorial review of the application of photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy to the characterization of semiconductors is presented. The PL technique provides a contactless, non-destructive means for the identification of certain chemical impurities in semiconductors, and comparison of the spectral sharpness of PL features associated with the recombination of free and bound excitons provides a qualitative measure of crystal quality. PL and tunable dye laser PLE spectroscopy of shallow acceptors and acceptor excited states are discussed briefly, but particular emphasis is placed on PL studies of deep impurity states. The 3d transition metals are the most common inadvertent deep impurities in III-V and II-VI semiconductors and PL techniques have been applied to the study of the details of their incorporation in these materials. The role of Cr and Fe dopants in the production of semi-insulating GaAs and InP has been studied extensively by PL techniques. Comparison of PLE spectra of radiative d-d transitions associated with transition metal impurities with published absorption spectra for the same dopants allows identification of the luminescent charge state. PL techniques have also proven useful in the characterization of ion implanted semiconductors. The assessment of lattice reconstruction during annealing, the optical activation of implanted impurities, and the study of the redistribution of impurities such as Mn, Fe, and Cu and surface degradation resulting from implantation and annealing procedures are examples of the application of PL techniques to the evaluation of the ion implantation technology in III-V semiconductors.