We have studied the structure and physical properties of an aluminum thin film grown on a (100) GaAs substrate. The X-ray diffraction (XRD) data shows that the Al film grown in situ by molecular beam epitaxy (MBE) is single crystalline. Compared with the polycrystalline film ex situ evaporated using an electron-gun (E-gun), the MBE-grown Al film has a high optical reflectivity in the visible and ultraviolet (UV) regime. In addition, the MBE-grown film has a 2-order-lower residue resistance, a 1-order-higher temperature coefficient of resistance, and a 2-order-larger magnetoresistance (MR) than the polycrystalline film. Owing to the long mean free time, the bulk-like electron-to-hole transition of Hall resistivity is observed for the first time in a nanoscale metal thin film. Our results suggest that MBE-grown Al thin films have great potential applications in metal-based nanoelectronics and nanophotonics.

In this work, it is demonstrated that the negative capacitance effect of ferroelectric Hf1−xZrxO2 transistor is highly correlated with Zr doping concentration. A steep subthreshold swing of 40 mV/decade, a low off‐state leakage current of 190 fA μm−1, and a large on/off current ratio of >107 can be simultaneously achieved in optimized negative capacitance Hf1−xZrxO2 transistor. Besides, the Zr diffusion issue and non‐ferroelectric phases significantly affect the multi‐domain switching of polycrystalline Hf1−xZrxO2. Therefore, an appropriate amount of Zr substitution is more favorable for both boosting ferroelectric and implementing the negative capacitance switch.

In this work, we report a novel multi-PNPN-channel junctionless transistor with short channel length of 60nm. The multi-PNPN junctionless transistor exhibits the larger drive current of >1μA/μm, the steeper turn-on switching of 77 mV/decade, and the higher on/off current ratio of >10 7 than the hybrid PN channel device under the same gate overdrive. The improved performance is mainly attributed to the enhanced depletion effect of multi-PNPN channel to optimize the electric field modification of surface p-channel. The stronger immunity to constant-voltage stress is also obtained for multi-PNPN channel due to the lower lateral electric field near drain side to reduce the impact ionization ratio.