Ambipolar carrier diffusion in In0.53Ga0.47As single quantum wells

The microluminescence surface scan technique (MSST) has been used to invest igate photocarrier diffusion in undoped In0.53Ga0.47As- InP single quantum well (QW), in the temperature (T) range from 15 K to 295 K. Narrowing of th e photoluminescence (PL) spatial profile is observed as the temperature is lowered, indicating reduction of the photocarrier diffusion length upon coo ling. It was found that the width of the PL spatial profile follows a linea r function of temperature, but a change in slope by a factor of 2.6 is obse rved at about 200 K, indicating a change of the dominant carrier scattering mechanism. In the temperature range of 15 K to 200 K, the ambipolar photoc arrier diffusion mechanism seems to be correlated to impurity states therma lly activated.