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Öğe Electron-transport properties of a ZnMgO/ZnO hetero structure and the effect of ınterface roughness and ZnMgO thickness(Springer, 2015) Özdemir, B.; Yarar, Z.; Özdemir, M. D.; Atasever, O. S.; Özdemir, M.The electron-transport properties of a ZnMgO/ZnO hetero structure were studied by use of an ensemble Monte Carlo technique. There was no intentional doping in the profile and the entire charge is because of polarization of charges at the interface. Interface roughness, and the intensity of acoustic and optic phonon scattering were used in the ensemble Monte Carlo method to find the transport properties of the two-dimensional electron gas (2DEG). The low-field mobility characteristics of the structure were determined as a function of temperature, the thickness of the ZnMgO layer, and the interface roughness. The interface roughness was found to have a very large effect on the drift mobility of carriers, especially at low temperatures. It was observed that as the thickness of the ZnMgO increases the concentration of electrons increases whereas the mobility of the electrons decreases. The low-field mobility values obtained from ensemble Monte Carlo simulations were in agreement with published experimental data.Öğe Mobility Characteristics of ZnMgO/ZnO Heterostructures with Screening Effects(Pleiades Publishing, 2024) Yarar, Z.; Alyörük, M.D.; Çekil, H.C.; Özdemir, B.; Özdemir, M.The electron mobility characteristics of a ZnMgO/ZnO heterostructure are systematically investigated by an ensemble Monte Carlo method. Screening effects are included in all electron scattering mechanisms. The mobilities are calculated for a temperature range of 4 to 300 K and Mg contents ranging from 8.5 to 44%. In this range, dislocation scattering (DS) and interface roughness scattering (IFR) are highly effective for low and high values of Mg compositions, respectively. Screening effects must be considered in scattering mechanisms to achieve a reasonable agreement with existing experimental results. Our findings could be significant for the design and optimization of ZnO-based deviceÖğe Screening effects on the mobility properties in AlGaN/GaN heterostructures with varied Al content(World Scientific, 2022) Yarar, Z.; Cesur, D.; Alyörük, M.D.; Çekil, H.C.; Özdemir, B.; Özdemir, M.The electron mobility at a AlGaN/GaN heterostructure is calculated using an ensemble Monte Carlo (MC) technique where the emphasis is primarily given to screening effects and dislocation scattering. Calculations of electron steady-state velocity-field curves confirm that screening has significant effects on the transport properties of AlGaN/GaN heterostructures. The mobility calculations are obtained for Al-content (8-35%), thickness of AlGaN barrier (30-500Å) and for various temperatures (77-1000K). Based on our theoretical scattering rates calculations, we show that screening effects should be included for all scattering rates to obtain good agreement with experimental results. Besides, especially dislocation scattering should be taken into account to get mobility results that agree with experiments at low field values. Our overall results agree reasonably well with experimental studies. These results can be highly useful in design and optimization of GaN-based devices.
