Radiative recombination spectra of heavily p-type δ-doped GaAs/AlAs MQWS

We present a study of the photoluminescence properties of heavily Be delta-doped GaAs/AlAs multiple quantum wells measured at room and liquid nitrogen temperatures. Possible mechanisms for photocarriers recombination are discussed, with a particular focus on the peculiarities of the excitonic and free carriers-acceptors photoluminescence emissions occurring below and above the Mott metal-insulater transition. Moreover, based on a simple theoretical model, it is found that the critical impurities concentration to observe the Mott transition in the multiple quantum wells samples exhibiting 15 nm wells width and 5 nm thick barrier layers is approximate to 3 x 10(12) cm(-2).