【Member Intro】Westlake University —— Regular Member

Introduction

      Westlake University is a new type of institution of higher learning organized by social forces and supported by the state, formerly known as Zhejiang Westlake Higher Institute. On February 14, 2018, it was formally approved by the Ministry of Education. In accordance with the orientation of "high starting point, small and fine, research-oriented", the university is committed to gathering first-class teachers, building first-class disciplines, cultivating first-class talents, and producing first-class achievements, and striving to make outstanding contributions to the national strategy of rejuvenation the country through science and education and innovation driven development. By 2026, the strength of major disciplines will reach the world’s leading level, and make significant contributions to basic scientific research, original technological innovation, and transformation of scientific and technological achievements. And it is expected to become a new international high-level research university with reasonable setting, clear positioning, strong development potential and good social reputation.

      The total area of micro-nano platform of Westlake University is about 900 square meters, which is divided into four functional modules related to micro-nano processing and testing, including patterning, plasma etching, film preparation and advanced characterization. Among them, the ultra-clean laboratory of about 450 square meters including one thousand and one hundred levels is mainly equipped: double-sided alignment lithography machine, two-photon 3D lithography machine, electron beam exposure machine, micro-nano 3D printing system, induction-coupling plasma etching system, deep reaction ion erosion machine, plasma rubber machine, plasma enhanced chemical deposition system, atomic layer deposition equipment, magnetron sputtering coating machine, thermal evaporation evaporation coating machine, digital holographic microscope, helium ion imaging microscope, scanning probe microscope, Fourier transform infrared spectrometer, scanning near-field optical microscope, ultraviolet / visible / infrared spectrophotometer, X-ray CT, surface steps, ellipsomeimeter and other advanced instruments and equipment. Micro-nano platform is an important technical platform for discipline construction and for promoting discipline development through interdisciplinary disciplines in Westlake University, as well as an important window for carrying out academic exchanges and cooperative research inside and outside the university. It provides all the principal investigators and research teams of the university with professional technical support on the basic and frontier scientific research in microelectronics, micro-nano photoelectric devices, biotechnology chips, new sensor parts, new 3D additive manufacturing and other fields. The open micro-nano platform will provide services to domestic and foreign universities, research institutes, enterprises and other units, and actively participates in international cooperation projects, and hopefully become a generic technology innovation platform and manufacturing and a talent training base in the field of micro-nano technology in 7-10 years.

      Adhering to the concept of "Advanced, Scientific and Innovative", the Material Science Public Experimental Platform of Westlake University focuses on the research of energy, environment and biomedical materials in the frontier fields of material science, supplemented by large-scale shared facilities and equipment and senior professionals to provide technical support for the characterization and analysis of the overall system. In Yunqi Campus, the platform focuses on the construction direction of material science related disciplines of Westlake University, and is equipped with a series of high-end advanced equipment in many fields such as morphology characterization, structural analysis, surface analysis, composition analysis, magneto and electrical properties, thermal and optical comprehensive performance characterization and material preparation. At present, the platform has ultra-high vacuum interconnection system (integrated STM, Laser-ARPS, XPS, OxMBE, PLD), single crystal / thin-film / powder XRD, PDF, PPMS, MPMS, diluting refrigerator, SEM, AFM, laser heat conductivity, rheometer, dynamic light scattering meter, floating melting zone single crystal growth furnace and other cutting-edge research equipment, and equipped with experienced high level professionals. The platform not only gives into account the conventional analysis characterization research needs, but also tracks the discipline frontier, continuous progress, and provides good characterization support for the cutting-edge basic scientific research in the world today.

Micro nano processing platform

Material Science Platform

Research Program

      The Advanced Solid-state Semiconductor Laboratory focuses on the development of next- generation of semiconductor materials, including wide band-gap oxide semiconductors, III-V nitride films, and 2D materials (graphene, hBN and TMDCs). The goal is to develop a multi-scale heterogeneous integration platform of various semiconductor thin films and explore their new physicochemical properties to realize the multiple functions needed for emerging applications such as the Internet of Things, artificial intelligence, and human-machine interface.

      Gallium oxide has attracted great attention for its ultra-broadband gap and excellent electrical performance. The laboratory is committed to the development of technologies in gallium oxide materials, devices and applications, including:

1.High-quality growth and controllable doping of Ga₂O₃ homogenous and heteroepitaxial thin films,  including Molecular Beam Epitaxy (MBE), the high mass heterogeneous epitaxy of Ga₂O₃ on the sapphire, the precise growth of complex structures on the homogeneous and heterogeneous substrate, and the controllable doping of the film conductivity. At the same time, the research of high speed and high quality growth of Ga₂O₃ based on halide vapour phase epitaxial system (HVPE) is also carried out.

2.Exploration of frontier scientific issues such as multiscale heterogeneous integration of various materials, including Ga₂O_3, and P-type Ga₂O₃ conductivity.

3.Development of Ga₂O₃ power devices (SBD, MOSFET, etc.) and optical detectors. New technology on Ga₂O₃ devices, which enables the best performance of the material.

MBE

HVPE

Research Team

      Kong Wei, a distinguished researcher at the School of Technology, Westlake University, bachelor's degree in physics from Sun Yat-sen University; PhD in Electronic Engineering from Duke University; From 2016 to 2020, he carried out postdoctoral research in the Department of Mechanical Engineering at MIT. He is a Shell Energy Scholar. He joined Westlake University School of Engineering full-time in September 2020. Dr. Kong Wei has published papers in Science, Nature Materials, Nature Nanotechnology, Nano Lett. and other journals as the first author or corresponding author, and the results have been reported by Semiconductor Today, Science Daily,phys.org, MIT News and other professional media. Among them, seven international patents are authorized by two American semiconductor companies to put into production.

      The Advanced Solid-state Semiconductor research team consists of three postdocs, eight doctoral students and a number of research assistants. Relying on the Key Laboratory of Westlake University and the university-level scientific research platform, the team has realized the high-quality growth and device preparation of a variety of new semiconductor materials, including gallium oxide. At present, it has made breakthroughs in gallium oxide epitaxial growth, controllable doping, photoelectric device development and other fields and applied for a number of related patents.

Achievements

1.The laboratory has achieved high-quality homogeneous epitaxial growth of Ga₂O₃ based on molecular beam epitaxial system, including epitaxial growth on commonly used crystal surfaces of (100), (-201) and (001) surfaces. The system can accurately control the growth mode and speed of the film to minimize the defects produced in the epitaxial process and achieve the best epitaxial quality. At the same time, the precise control of (Al_xGa_1-x)₂O₃ and (In_xGa_1-x)₂O₃ ternary oxide components is also realized. The band width of Ga₂O₃ can be effectively regulated through ternary combination, and it has a good mutation interface, which lays a foundation for the preparation of high-performance gallium oxide devices. In addition, the controllable doping of conduction of N-type Ga₂O₃ can also be realized in this system, and the controllable gradient doping of Si and Sn has been mastered. Device-level homogeneous epitaxy of Ga₂O₃ multi-structure functions has been realized using the MBE system.

2.In order to realize the heterointegration of Ga₂O₃ and reduce the substrate cost, the laboratory has carried out the Ga₂O₃ heteroextension study simultaneously. At present, epitaxial growth on GaN and sapphire substrate has been realized, and some progress has been made in inhibiting defects and twin generation, significantly improving the quality of Ga₂O₃ heteroepitaxial.

3.Compared with molecular beam epitaxial systems, halide vapour phase epitaxial system (HVPE) has faster growth rate and lower equipment maintenance costs, and has more potential in the field of Ga₂O₃ vertical device preparation and industrialization. The HVPE system developed in this lab grows Ga₂O₃ (-201) surfaces on sapphire at over 10um / h. Currently, the epitaxial quality is being gradually improved and the backbottom doping is being suppressed.

4.Based on the school micro-nano platform, the laboratory has developed a complete set of device preparation technologies, including a series of standard processes such as lithography, etching and passivation. At present, Ga₂O₃-based photodetector has been successfully prepared, and the epitaxial quality of Ga₂O₃ film has been verified. For the next step, the laboratory will continue to explore the manufacturing of high-performance Ga₂O₃-based power electronics, in order to release the huge potential of the material in the field of power electronics.

gallium oxide heteroepitaxy

gallium oxide-based photodetector