PHOTOREFLECTANCE OF INSB AT THE E(1) AND E(1)+DELTA(1) TRANSITIONS

The photoreflectance at high interband transitions (E1 and E1 + DELTA1) is obtained at 8 K for InSb bulk samples. For a p-type sample, the lineshape is well reproduced by Aspnes third derivative model, while for an undoped sample, the photoreflectance spectra is better reproduced by a first derivative of an exciton lineshape, suggesting the presence of a saddle-point exciton at low temperature. The transition energies determined from the spectra indicate an excitonic resonance at about 12 meV below the interband transitions in agreement with the 2D exciton model. The transition broadenings obtained from the first derivative function agree with the rigid pseudo-ion model predictions.