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We study the effects of GaN interlayer on the transport properties of two-dimensional electron gases confined in lattice-matched AlInN/AlN/GaN heterostructures. It is found that the Hall mobility is evidently enhanced when an additional ultrathin GaN interlayer is introduced between AlInN and AlN layers. The enhancement of the Hall mobility is especially remarkable at low temperature. The high Hall mobility results in a low sheet resistance of 23Ω=⧠ at 2K. Meanwhile, Shubnikov-de Haas oscillations (SdH) are also remarkably enhanced due to the existence of GaN interlayer. The enhancement of the SdH oscillations is related to the larger quantum mobility μq owing to the suppression of the interface roughness, alloy disorder, and ionized impurity scatterings by the GaN interlayer. [ABSTRACT FROM AUTHOR]

The oscillatory magnetoresistance of the two-dimensional electron gas (2DEG) in AlxGa1-xN/GaN heterostructures has been studied by means of magnetotransport measurements at low temperatures and high magnetic fields. The split peaks of the Shubnikov–de Haas oscillations are observed at high magnetic fields, which are attributed to the spin splitting of the 2DEG. It is found that the spin splitting energy becomes smaller with an increase in magnetic field, indicating that the Zeeman spin splitting is not dominant at measured magnetic field range. Within this magnetic field range, the zero-field spin splitting, as well as Zeeman spin splitting, affects the split peaks in the oscillatory magnetoresistance of the 2DEG in AlxGa1-xN/GaN heterostructures. [ABSTRACT FROM AUTHOR]

The weak antilocalization effects of the two-dimensional electron gas in a high mobility AlxGa1-xN/GaN heterostructure have been investigated by means of magnetotransport measurements before and after illumination. The zero-field spin splitting mainly arising from the Rashba spin-orbit coupling effect as a function of electron concentration as well as a function of temperature is studied using the weak antilocalization analysis. The Rashba spin-orbit coupling constant α deduced using the weak antilocalization analysis shows a rapid decrease with the increase of the measured electron concentration. [ABSTRACT FROM AUTHOR]