Erik Jonsson School of Engineering & Computer Science Materials Science and Engineering UT Dallas

















Our research group combines innovative materials growth, interface and chemical bonding analysis, and state-of-the-art devices to significantly enhance the knowledge and performance capabilities of nanoelectronic, optoelectronic, and energy storage applications.  Our approach utilizes advanced molecular beam epitaxy techniques and highly developed materials characterization to fundamentally understand the growth process, material nanostructure, chemical bonding, and experimentally determined band structure.  We then correlate those findings with advanced electrical transport measurements in devices that we fabricate to take full advantage of the novel properties of the materials and heterostructures that we create.  Our current research is strongly focused on the development of 2D materials, topological insulators, and heterostructures for advanced low-power logic and memory devices.

We have established collaborations with other researchers in Materials Science, Physics, Electrical Engineering, and Chemistry.  We work closely with researchers at NIST, SLAC National Accelerator Laboratory, and the Army Research Labs and from other universities (including Notre Dame, UC Berkeley, Penn State, Purdue, UT-Austin, Georgia Tech, Dublin City University), and we maintain ongoing projects and collaborations with U.S. and International Industries (Texas Instruments, Intel, TSMC, Samsung, Applied Materials, Global Foundries, Tokyo Electron).  

In our lab, a unique multi-chamber MBE has been established with each of the VG-Semicon growth chambers linked together with a UHV transfer tube system operating at a base pressure of about 10-11 mbar.  II-VI growth is performed in a V80H growth chamber equipped with two vertical e-beam evaporators, enabling the growth of high melting temperature metals such as Hf, Mo, W, and Fe, in addition to effusion cell evaporation of Se, Te, Zn, Bi, and Be.  The two e-beam evaporators allow for TMD and topological insulator heterostructure growth as well as mixed transition metal TMDs and magnetic doping, providing significant flexibility in material and device design. The chamber is also equipped with ZnCl2 and nitrogen plasma sources for doping and surface functionalization.  The III-V chamber is also a V80H with recently upgraded hardware and software to provide state-of-the-art growth capabilities including In, Ga, As, B, Al, and N compounds as well as in-situ H-cleaning and Be and Si doping.  The Group IV chamber, a V90S, is used to grow Si, Ge, and Sn epitaxial films,SiSnGe compounds, and strained heterostructures.  The vertical growth chamber in this system incorporates electron-beam evaporators and effusion cells for Sb and B doping.  Preparation chambers with high temperature heating stages are available for each material system.  Each growth chamber is equipped with in-situ RHEED allowing us to assess the growth quality in real-time.

MBE System

These MBE capabilities allow us to study materials that are important for a number of applications such as:

  • Transition Metal Dichalcogenides:WSe2 TFET   We are investigating the MBE growth and characterization of an exciting class of 2-Dimensional materials known as transition metal dichalcogenides (TMD).  TMDs are layered materials somewhat analogous in that respect to graphene.  Unlike graphene though, through the strategic selection of transition metal and chalcogen, we can tune the electronic properties of these materials making semiconductors with useful electronic properties.  As layered 2D materials, these materials can be grown on many different substrates through weak van der Waals interactions, drastically reducing the impact of lattice mismatch on the quality of the crystal growth.  We are currently focused on growing these materials with useful electronic structure for applications such as the tunnel FET (image at right) and the BiSFET.  With our two e-beam evaporators we have succesfully grown Hf, Mo, and W based dichalcogenides including mixed TM and mixed chalcogen TMDs as well as magnetic doping of these TMDs.
  • Topological Insulators:Bi2Se3 TEM   We are growing topological insulators (TIs), an interesting class of materials that have topologically protected spin polarized carriers on their surfaces or edges.  We are investigating the MBE growth of both 3D TIs (Bi2Se3) and 2D TIs (monolayer Bi and 1T' TMDs) to integrate them into novel, very low-power and high speed logic and memory devices.  We have recently demonstrated high-quality growth of Bi2Se3 (right) and monolayer Bi and are in the process of determining their topological properties by ARPES and STM/STS. 
  • Ge, InGaAs, and GaN on Si(100): We are also studying the heterogeneous integration of alternative channel materials (Ge, InGaAs, and GaN) onto a bulk Si(100) platform.  Using techniques similar to aspect ratio trapping where we use patterned trenches in oxides to trap misfit dislocations, we are able to reduce defects that result from lattice mismatch and produce high quality FinFETs.  We have also developed software for the rapid extraction of quantum mechanically corrected C-V parameters for these alternative channel materials with high-k dielectrics.