Applied Physics Letters · 2002 · 59 citations · 11 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsCarrier TransportDopingSemiconductor Device MaterialsSemiconductor PhysicsSemiconductor SurfacesWide-bandgap SemiconductorsCarrier Transport MechanismsElectron MobilityElectronic Trap StatesGallium Nitride (Gan) MaterialsMolecular Beam EpitaxyPit DensityTrap StatesTrapping Effects
The effect of growth regime on the deep level spectrum of n-GaN using molecular-beam epitaxy (MBE) was investigated. As the Ga/N flux ratio was decreased towards Ga-lean conditions, the concentration of two acceptor-like levels, at Ec−3.04 and 3.28 eV, increased from 1015 to 1016 cm−3 causing carrier compensation in these films. Thus, these two traps behaved as the dominant compensating centers in MBE n-GaN. Furthermore, the increase in trap concentration also strongly correlated with the degradation of both surface morphology and bulk electron mobility towards Ga-lean conditions, where higher pit densities and lower mobility were observed. These results show that the growth regime directly impacts all morphology, bulk transport, and trap states in n-GaN.
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