Abstract
The photoluminescence (PL) of InAs and GaInAsSb/InAs epilayers grown by Gd-doped liquid-phase epitaxy (LPE) has been investigated using a double-modulation Fourier transform infrared spectrometer (FTIR). The spectra were composed of peaks due to band-to-band, band-to-impurities, and exciton recombinations. The excitation power, temperature and Gd concentration dependences of these features were studied. The temperature dependence of the band-to-band transition energies was examined by measuring FTIR transmission spectra and by comparing experimental results with those obtained with an empirical formula. A PL full width at half-maximum (FWHM) as narrow as 4.35 meV has been achieved for GaInAsSb epilayers grown from Gd-doped melt indicating high purity of epilayers. Raman scattering measurements of GaInAsSb epilayers showed a two-mode behavior for the optical phonons, indicating that homogeneous, high-quality epilayers were achieved.