Investigation into molecular beam epitaxial growth and characterization of InGaAs structures and InAs superlattices

Abstract

(1) InGaAs quantum wells have been experimentally studied for their potential application in electronic devices. The narrow band gap of InGaAs lead to smaller effective masses for electrons and holes, which results in higher mobilities in the well. In this work, the layer structure, doping and growth parameters of InGaAs wells were further optimized to obtain a higher density and mobility. At room temperature, an electron density of 2.2×10^12cm-2 with mobility of 12,800cm^2/Vs has been achieved in In0.64Ga0.36As quantum well.

(2)Source and drain regions of InGaAs based field-effect-transistors need to be heavily doped for low contact resistance. We studied doping efficiency at higher concentrations in In0.53Ga0.47As using Si as the n-type and Be as the p-type dopant. The maximum doping concentration achieved for n and p doping are 4.8×1019cm^3 and 1.3×10^20cm^ 3 , respectively.

(3)The carrier multiplication effect is an emerging research area in the next generation solar cell techniques. Favorable energy levels for carrier multiplication can be achieved in InAs/AlAsSb superlattices through quantum confinement. In this work, a series of InAs/AlAsSb superlattice structures were grown by molecular beam epitaxy on GaAs (001) and InAs (001) substrates. Structural assessment from high-resolution x-ray diffraction shows good compositional control of the superlattices. The superlattice structures display peak photoluminescence energies in the designed 0.7-0.8 eV spectral region.