Investigation of transport properties of doped GaAs epitaxial layer using open photoacoustic cell

An open photoacoustic cell under heat transmission configuration has been employed to evaluate the thermal and transport properties of n-type Si doped GaAs epitaxial layer and p-type Be doped GaAs epitaxial layer grown on GaAs substrate by molecular beam epitaxial method. The variation of the characteristics of the photoacoustic signal with chopping frequency clearly indicate the different heat generation mechanisms occurring in the sample under optical excitation at 2.54eV with laser beam. The values of thermal diffusivity, diffusion coefficient, surface recombination velocity and nonradiative recombination time have been evaluated for the sample by fitting the experimentally obtained phase of the photoacoustic signal with the theoretical model. It has been observed that the nature of dopant influences the values of thermal and transport properties of the semiconductor samples.