UCLA

The continued miniaturization of the silicon-based electronics has been the core of the information technology revolution, but such efforts are quickly approaching the fundamental material limit, which has motivated considerable efforts in exploring a new generation of electronic materials and device architectures. Among many material systems explored, two-dimensional (2D) atomic crystals, wide bandgap semiconductors and halide perovskite have attracted considerable interests for their unique physical geometry or excellent electronic, optoelectronic properties, offering a pathway for further miniaturization of digital devices or diversified function integration for Internet of Things and artificial intelligence. However, to probe the fundamental transport of these materials and capture their intrinsic merits in functional devices is a nontrivial challenge since these materials are usually rather delicate and may readily degrade during the material integration and device fabrication steps. To this end, a physical transfer process exploiting the weak van der Waals (vdW) force to combine disparate materials to form heterojunction interfaces with atomically clean and electronically sharp vdW interfaces, allowing creating high-performance devices for probing and pushing the limit of these emerging electronic materials. Here in this dissertation, we explore and optimize vdW integration of high-quality and uniquely designed device architectures for creating and investigating high performance devices of emerging electronic materials including 2D atomic crystals, bulk β-Ga2O3 and single crystalline lead halide perovskites. We first show the potential of integrating metal contacts with sub-10 nm channel length to 2D materials for probing quantum transport and pushing the on-current for breaking the miniaturization limit of silicon. Then we demonstrated various high-performance vdW heterojunctions based on 3D semiconductors including Schottky diode, p-n diode, metal semiconductor field effect transistors and junction field effect transistors to unlock a rich material library for vdW integration. We also design a feedback gate structure to suppress the threshold voltage roll-off and undesired ambipolar transport in 2D semiconductors, which are crucial for stable device operation for integrated circuits but have seldomly been explored. Finally, we develop a convenient and scalable vdW plug-and-probe technique to integrate top-gate and contact structures on 2D materials and halide perovskite in one step to form ideal transistors for intrinsically probing these novel materials and fabricating high-performance devices. By increasing both complicity of device architectures and the variety of channel material choices while still capturing the merits of these emerging electronic materials, we prove the vdW integration as a universal approach providing prominent opportunities to both fundamental study for novel materials as well as the design of next-generation devices in future semiconductor industry.