Fourier transform analysis of electromodulation spectra: Effects of the modulation amplitude

Abstract
Fourier transform analysis of Franz-Keldysh oscillations is applied to electroreflectance spectra of GaAs p–i–n diode structures in order to elucidate the role of the modulation amplitude in electric-field-modulated spectroscopies. The effects of modulation amplitude are quantitatively evaluated by considering the imaginary and real parts of the complex Fourier transform in addition to its modulus. The experimentally measured electroreflectance spectra and their Fourier transforms are in good agreement with model calculations.