Optical and transport properties of GaGeTe single crystals

GaGeTe single crystals were grown using a modified Bridgman method. The prepared samples were characterized by X-ray diffraction and investigated using measurements of the reflectance in the plasma-resonance-frequency region and measurements of the transmittance spectra in the MIR, NIR and VIS regions. An analysis of the plasma resonance indicates a near-degenerate state in the GaGeTe single crystal. The variation of the square of the absorption coefficient, α2, as a function of incident radiation energy showed two distinct minima of α located at ≈0.5 and ≈1.0eV. The free carrier scattering mechanism was estimated from the slope of the long-wavelength edge. The transport measurement evidence of single-crystalline GaGeTe is a degenerate p-type semiconductor with a concentration of holes of p≅5.1019cm−3. The mobility of the holes is rather low. •Single crystals of GaGeTe were grown using the Bridgman technique.•GaGeTe is p-type semiconductor with optical band gap Eg=1.12eV.•Native defects produce concentration of holes p≅5×1019cm−3.•Dominant scattering mechanism is on acoustic phonons and ionized impurities.•Despite high hole concentration GaGeTe shows high Seebeck coefficient.