Near-infrared Near-field Imaging Spectroscopy of Localized Electronic States due to Composition Fluctuation in GaInNAs Quantum Wells

Near-field photoluminescence spectroscopy of a GalnNAs quantum well with a spatial resolution of 50-150 nm (lambda/20- lambda/8) was performed to visualize the bandgap fluctuation, which reflects the nonuniform distribution of N and In atoms. We quantitatively estimate the real-space potential profile and fluctuation of N concentration in combination with numerically solving Schrodinger equation.