The relation between optical instabilities and absorbed material in   photoluminescence with [0001] InGaN single quantum well
  In this letter, we aim to elucidate the physical mechanism of the so called optical memory effect and blinking phenomenon observed in InGaN single quantum wells (SQW). We have found that the optical response of both memory effect and blinking phenomenon, is affected by different excitation wavelengths and by the change of gas adsorption on the crystal surface. A model that reproduce dynamics of the coverage of absorbed gas molecules on the sample surface is given and compared with experimental data with evident match. 
T. Tsutsumi, G. Alfieri, Y. Kawakami and R. Micheletto
physics.optics cond-mat.mtrl-sci