Metal-organic vapor phase epitaxial growth of InGaAs/GaAs and GaAsN/GaAs multiquantum-well (MQW) structures was monitored by in situ reflectometry at 635 nm using a normal incidence reflectance setup. The reflectance signal is found to change significantly during both quantum-well (QW) and barrier growth regions. A matrix method is used to calculate the theoretical reflectance curve and comparing the theoretical curves to the measured ones the complex refractive index of the ternary alloys are derived. Consequently, when the behavior of the complex refractive indices of InGaAs and GaAsN is known as a function of composition, the composition of all the QWs in the MQW strucure can be determined in situ.
Reentilä, O., Mattila, M., Sopanen, M., & Lipsanen, H. (2007). In-situ determination of InGaAs and GaAsN composition in multi-quantum-well structures. Journal of Applied Physics, 101(3), 1-5. . https://doi.org/10.1063/1.2435065