Room temperature photoreflectance (solid blue lines) and surface photovoltage spectroscopy spectra (red dashed lines) for three GaAs0.988N0.012/GaAs QWs of different widths. The spectral features are assigned as QW GS and QW ES for the ground and excited state optical transitions, respectively.
Results of fitting procedure for the example of 10 nm well from Fig. 1 , for both PR and DSPS spectra.
Well width dependence of the transition energies of GaAs0.988N0.012/GaAs quantum wells calculated by using the 10-band k·p Hamiltonian if the electron effective mass is from BAC model (Ref. 18 ). The red, blue, and green lines (solid—heavy hole transitions; dashed—light hole transitions) represent the calculated values if the conduction band offset are equal to 70%, 80%, and 90%, respectively.
Well width dependence of the transition energies of GaAs0.988N0.012/GaAs (a) and GaAs0.978N0.022/GaAs (b) quantum well calculated by using the 10-band k·p Hamiltonian if the electron effective mass is from Ref. 33 (dashed red line) and if the electron effective mass is equal to 0.09 for x = 1.2% N (a) and 0.15 for x = 2.2% N (b) (solid black line).
Effect of increasing N mole fraction on the electron effective mass. Data points: experimental mass values taken from Ref. 19 (Δ), Ref. 21 (○), our results (●). The dashed black lines presents results from Ref. 20 . The dashed red line presents calculated values from BAC model (Ref. 18 ). The dashed blue line presents results from Ref. 33 . The dashed green line, calculated values with GaAs1−xNx/GaAs QW electron effective mass given by Eq. (2) .
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