Advanced Materials · 2017 · 144 citations · 37 references
EngineeringElectrical EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsHigh-frequency Semiconductor DevicesSemiconductor Device MaterialsSemiconductor HeterostructuresThin Film StrainWide Band Gap SemiconductorsWide-bandgap SemiconductorsElectron MobilityEpitaxial Film GrowthFlexible SubstratesGallium NitrideGan-based High-frequency DevicesHeterostructuresHigh-electron-mobility TransistorsStrain Effects On Electronic Properties
Abstract Flexible gallium nitride (GaN) thin films can enable future strainable and conformal devices for transmission of radio‐frequency (RF) signals over large distances for more efficient wireless communication. For the first time, strainable high‐frequency RF GaN devices are demonstrated, whose exceptional performance is enabled by epitaxial growth on 2D boron nitride for chemical‐free transfer to a soft, flexible substrate. The AlGaN/GaN heterostructures transferred to flexible substrates are uniaxially strained up to 0.85% and reveal near state‐of‐the‐art values for electrical performance, with electron mobility exceeding 2000 cm 2 V −1 s −1 and sheet carrier density above 1.07 × 10 13 cm −2 . The influence of strain on the RF performance of flexible GaN high‐electron‐mobility transistor (HEMT) devices is evaluated, demonstrating cutoff frequencies and maximum oscillation frequencies greater than 42 and 74 GHz, respectively, at up to 0.43% strain, representing a significant advancement toward conformal, highly integrated electronic materials for RF applications.
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Transfer printing by kinetic control of adhesion to an elastomeric stamp
Matthew Meitl, Zhengtao Zhu, Vipan Kumar et al. · Nature Materials · 2005 · 1.5K citations