Spectral Resolution Effects on the Lineshape of Photoreflectance

Spectral resolution effects on the lineshape of photoreflectance (PR) spectroscopy is experimentally investigated. PR measurements are performed on HgCdTe epilayer and InAs/GaAs quantum dot (QD) low-dimensional samples at low temperatures in a spectral resolution range from 8 to 0.5 meV. The results indicate that the resolution affects not only the identification of narrow PR features, but also the determination of critical-point energies of identified PR features, and a spectral resolution of as high as 0.5 meV may be necessary for low-dimensional semiconductors. The spectral resolution is indeed a crucial parameter, for which the step-scan Fourier transform infrared spectrometer-based PR technique is preferable.