Photoreflectance 측정에 의한 InxGal-xP의 특성 연구

A Study of Characteristics of InxGal-xP by Photoreflectance measurement

  InxGa<SUB>1-X</SUB>P/GaAs structures were grown by chemical beam epitaxy(CBE). Pure phosphine (PH₃) gases were used as group V sources. For the group Ⅲ sources, TEGa, TmIn were used. InxGa<SUB>1-X</SUB>P epilayer was grown on SI­GaAs substrate and has a 1­㎛ thick. We have investigated the characteristics of InxGa<SUB>1-X</SUB>P by the photoreflectance(PR) spectroscopy. The PR spectrum of InxGa<SUB>1-X</SUB>P shows third derivative feature whose peaks provide energy gap. The energy gap of InxGa<SUB>1-X</SUB>P has deduced composition x. From temperature dependance of PR spectra, temperature coefficient is dEg/dT=-3.773×10？⁴ eV/K, and Varshni coefficients a and β values obtained 4×10？⁴ eV/K and 267 K respectively. Also, interaction αB was 19.4 meV using the Bose­Einstein temperature relation, and Θ value related the average phonon frequency were 101.4 K. In particular, shoulder peak related to defects observed in PR signal that measured in temperature 82 K.