Liu, T.-A.T.-A.LiuPan, C.-L.C.-L.PanGONG-RU LIN2018-09-102018-09-102001http://www.scopus.com/inward/record.url?eid=2-s2.0-17044452839&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/293518The influence of Al0.05Ga0.95N cap thickness and growth temperature on the electrical properties of the Al0.05Ga0.95N/GaN two-dimensional electron gas (2DEG) was investigated. Varying the thickness of the Al0.05N barrier led to regions in which the dominant 2DEG scattering mechanisms were either Coulombic or interface roughness/alloy disorder scattering. The 2DEG sheet carrier concentration was found to increase with Al0.05Ga0.95N cap thickness and saturated at ∼25 nm. By increasing the growth temperature from 650°C to 750°C, the measured low temperature 2DEG sheet carrier concentration was found to decrease and the measured low temperature mobility was found to increase while the Al composition remained constant. Temperature dependent Hall measurements revealed that by increasing the growth temperature, the incorporation of impurities is decreased. A maximum 77 K mobility of ∼19,000 cm2/Vs was observed for films grown at 750°C with 20 nm thick Al0.05Ga0.95N caps.2DEG; Aluminum gallium nitride; Gallium nitride; Heterostructure; Mobility; Molecular beam epitaxy; Nitrides; Sapphire; TransportCarrier concentration; Electric properties; Electric variables measurement; Electron gas; Electron scattering; Electron transport properties; Molecular beam epitaxy; Plasma applications; Semiconducting aluminum compounds; Semiconducting gallium compounds; Surface roughness; Thermal effects; Aluminum gallium nitride; Growth temperature; Hall measurements; Plasma assisted molecular beam epitaxy; Two dimensional electron gas; Heterojunctionsjournal article2-s2.0-17044452839