We demonstrate the potential of a novel hybrid nanostructure three-dimensional graphene (3D-C) coated with boron nitride (BN) as an electromagnetic interference (EMI) shield. BN, deposited by sputtering, encapsulates 3D-C to form a light-weight graphene based EM shield that has an electrically insulating exterior. The BN deposited on 3D-C was homogeneously distributed with even coverage on the struts of 3D-C. EMI shielding results have shown that the hybrid material has a total shielding effectiveness (SET) of 53dB and 58dB in the X band and Ku band respectively.

AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMT) with a low-temperature epitaxy (LTE)-grown single crystalline AlN gate dielectric were demonstrated for the first time and the post-gate annealing effects at 400 °C were studied. The as-deposited LTE-AlN MISHEMT showed a maximum drain current (IDmax) of 708 mA/mm at a gate bias of 4 V and a maximum extrinsic transconductance (gmmax) of 129 mS/mm. The 400 °C annealed MISHEMT exhibited an increase of 15% in gmmax, an order of magnitude reduction in reverse gate leakage and about a 3% suppression of drain current (ID) collapse. The increase of gmmax by post-gate annealing is consistent with the increase of 2DEG mobility. The suppression of ID collapse and the reduction of gate leakage current is attributed to the reduction of interface state density (5.0 × 1011 cm−2eV−1) between the AlN/GaN interface after post-gate annealing at 400 °C. This study demonstrates that LTE grown AlN is a promising alternate material as gate dielectric for GaN-based MISHEMT application.

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Vertically ordered hexagonal boron nitride (h-BN) films were successfully sputtered on AlGaN/GaN heterostructure (HS) using high power impulse magnetron sputtering at room temperature. The h-BNs vertical ordering along the (0002) plane was confirmed using high-resolution transmission electron microscopy. After the h-BN deposition, degradation of two-dimensional electron gas (2DEG) properties was observed in AlGaN/GaN HS. Full recovery of 2DEG mobility, along with an improvement in sheet resistance and an increase in sheet carrier concentration was obtained after rapid thermal annealing at 500 °C for 300 s in a N2 atmosphere, which is due to the reduction of sputtering related structural damage.

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