X-ray photoelectron spectroscopy analysis of TlInGaAsN semiconductor system and their annealing-induced structural changes

TlInGaAsN thin films grown by gas-source molecular-beam epitaxy were investigated by x-ray photoelectron spectroscopy (XPS) to analyze the Tl incorporation and to study the annealing-induced transformation of the atomic configurations. XPS analysis revealed that the Tl composition in the grown TlInGaAsN is around 1.5% and that the dominant atomic configuration of the TlInGaAsN changes from the In-As and Ga-N bonds to the In-N and Ga-As bonds by 700 deg. C rapid thermal annealing. High-resolution x-ray diffraction and reciprocal space mapping measurements showed that no significant out-diffusion of the elements occurs in the TlInGaAsN/TlGaAsN quantum wells (QWs) even after the same annealing. It is concluded that the blueshift in the photoluminescence peak for the TlInGaAsN/TlGaAsN QWs after annealing is attributed to the transformation of the atomic configuration in TlInGaAsN.