Quantitative Analysis of In Density in Semi-Insulating GaAs by Photoluminescence

Photoluminescence (PL) measurements at 4.2 K were performed on In-doped semi-insulating GaAs (In x Ga 1- x As) grown as a nearly dislocation-free substrate for GaAs large-scale integrated circuits. The In composition x of the sample wafers was calibrated by inductively-coupled-plasma emission spectrometry before the PL measurement. A small variation of In composition in the region 0 ≤ x ≤0.0139 was detected by the peak-energy shift of exciton-recombination emissions Δ h ν (eV). The value of x could be estimated from Δ h ν using the equation x =- Δ h ν/1.505 without destruction of the sample wafers. It was found that the emission of neutral-acceptor-bounded-exciton recombination observed in all samples was useful for the measurement of the x value.