Carrier De-trapping from the Sub-bandgap States: A novel mechanism in InGaN/GaN systems manifested by ultrafast pump-probe spectroscopy

Abstract

Sub-bandgap states in GaN-based quantum confined structures are not always disadvantageous for efficient light emission. A novel intrinsic mechanism of carrier recovery from sub-bandgap states through Coulombic interaction is proven. Indium inhomogeneity is established as carrier reservoirs that can hold carriers for future recombination. There is a finite probability of electron de-trapping from these states, instead of recombining through opposite charge.