Mechanisms of Thermal Quenching of Defect-Related Luminescence in Semiconductors

The intensity of defect-related photoluminescence (PL) in semiconductors changes with temperature, and it usually decreases exponentially above some critical temperature, a process called the PL quenching. Herein, main mechanisms of PL quenching are reviewed. Most examples are given for defects in GaN as the most studied modern semiconductor, which has important applications in technology. Peculiarities of defect-related PL in I-VII, II-VI, and III-V compounds are also reviewed. Three basic mechanisms of PL quenching are distinguished. Most examples of PL quenching can be explained by the Schon-Klasens mechanism, whereas very few or even no confirmed cases can be found in support of the Seitz-Mott mechanism. Third mechanism, the abrupt and tunable quenching, is common for high-resistivity semiconductors. Temperature dependence of capture coefficients and a number of other reasons may affect the temperature dependence of PL intensity. The "negative quenching" or a significant rise in PL intensity with temperature is explained by a competition between recombination channels for minority carriers.