Effect of Annealing on Electronic Transport in Modulation-doped In0.32Ga0.68As/GaAs Quantum Well Structures

İngilizce (OpenAlex)

In this study, electronic transport properties of n-type modulation-doped In0.32Ga0.68As/GaAs quantum well (QW) quasi 2D structures and the effects of post-growth rapid thermal annealing and growth temperature are determined. Electron Hall mobility and carrier concentration of In0.32Ga0.68As/GaAs QW were determined using the Hall effect measurement at a temperature range between 4.2 K and 300 K. While the low-temperature electron mobility has temperature-independent behavior, electron mobility at high-temperatures deteriorates drastically. However, for low-temperature growth samples, electron mobility shows a slight increase at lower temperatures. The effects of annealing and growth temperature on electronic transport properties are investigated and compared in terms of carrier mobility, carried density, effective mass and scattering mechanisms. To determine the dominant scattering mechanisms in the 2D structures of In0.32Ga0.68As/GaAs, temperature-dependent Hall mobility results are fitted using an analytical model, considering all possible scattering mechanisms (interface roughness, alloy disorder, acoustic phonon, polar optical phonon and remote ionized impurity scattering) in the 2D samples. Magnetotransport (MR) measurements were carried out between 4.2 K and 50 K and the effective mass, Fermi level, and 2D carrier density were calculated by analyzing amplitudes of temperature dependence Shubnikov de Haas (SdH) oscillations. Our results indicate that the effects of annealing at 700◦C-600s reduce interface roughness and alloy disorder scattering, thereby enhancing electron mobility. Post-growth thermal annealing improved electron mobility. Also, annealing increases the effect mass and causes a reduction in the electron concentrations of the InGaAs/GaAs QW systems. Additionally, thermal annealing increases the effective electron mass while decreasing electron concentration.