Randall Feenstra

Department of Physics, Carnegie Mellon University
Ph.D., California Institute of Technology
Summary:

The research activities of my group deal with structural and electronic properties of semiconductor materials and devices. A major tool used in the studies is the scanning tunneling microscope, which allows one to image the atomic structure of a surface and to perform spectroscopic measurements of the electronic energy levels. Many of the studies deal with semiconductor heterostructures consisting of multiple layers of different types of material, with the goal of understanding how the structure of the device (including imperfections and defects) determines its electronic properties. Growth of semiconductor heterostructures has been performed in my laboratory using molecular beam epitaxy, for GaN in particular (a semiconductor with a relatively large band gap, used for blue light-emitting devices and for microwave transistor applications).

Most recently we have focused on the study of two-dimensional (2D) materials, including graphene and hexagonal boron nitride (h-BN). We prepare these materials by growth at high temperatures, and we characterize them using both scanning tunneling microscopy and low-energy electron microscopy. The latter permits both diffraction and imaging of the surfaces, with nm-scale resolution. Additionally, spectroscopic observation of energy levels above the vacuum level is performed, which is particularly useful for these 2D materials. Heterostructures consisting of alternating layers of graphene and h-BN are being studied, because of the unique current-voltage characteristic for tunneling in such structures.

Students

Vineetha Bheemarasetty

Undergraduate Student

vbheemar@andrew.cmu.edu
6408 Wean Hall, Pittsburgh PA, 65109

Affiliation:

Physics
Carnegie Mellon University

Jun Li

Graduate Student

junl2@andrew.cmu.edu
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Project:

Two-dimensional materials, growth, simulation, and characterization

Dacen Waters

Graduate Student

dwaters@andrew.cmu.edu
6408 Wean Hall, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Andrew Ye

Undergraduate Student

andrewy@andrew.cmu.edu
6408 Wean Hall, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Andrew Ye

Undergraduate Student

andrewy@andrew.cmu.edu
Wean Hall 6408, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Education:

  • B.S./B.Sc., Applied Physics, Carnegie Mellon University
Most Cited Publications
  1. "Tunneling spectroscopy of the Si(111)2 × 1 surface," R.M. Feenstra, Joseph A. Stroscio, A.P. Fein, Surface Science 181, 295 (1987)
  2. "Atom-selective imaging of the GaAs(110) surface," R. M. Feenstra, Joseph A. Stroscio, J. Tersoff, and A. P. Fein, Phys. Rev. Lett. 58, 1192 (1987)
  3. "Electronic Structure of the Si(111)2 × 1 Surface by Scanning-Tunneling Microscopy," Joseph A. Stroscio, R. M. Feenstra, and A. P. Fein, Phys. Rev. Lett. 57, 2579 (1986)
  4. "Tunneling spectroscopy of the GaAs(110) surface," R. M. Feenstra and Joseph A. Stroscio, J. Vac. Sci. Technol. B 5, 923 (1987)
  5. "Tunneling spectroscopy of the (110) surface of direct-gap III-V semiconductors," R. M. Feenstra, Phys. Rev. B 50, 4561 (1994)
Recent Publications
  1. "Formation of Graphene atop a Si adlayer on the C-face of SiC," J Li, Q Wang, G He, M Widom, L Nemec, V Blum, M Kim, P Rinke, and RM FeenstraarXiv (2019)
  2. "Coexistence of quantum spin hall edge state and proximity-induced superconducting gap in monolayer 1T'-WTe2," F Lupke, D Waters, SC de la Barrera, M Widom, DG Mandrus, J Yan, RM Feenstra, and BM Hunt.  arXiv (2019)
  3. "Role of Strain in Quantum-Confined States of Heterobilayers of 2D Materials," D Waters, F Lüpke, Y Nie, Y Pan, S Fölsch, YC Lin, B Jariwala, K Zhang, ... Bulletin of the American Physical Society
  4. "Davisson-Germer Prize in Atomic or Surface Physics Talk: Studies of Two-dimensional Materials using Tunneling Electrons," R Feenstra Bulletin of the American Physical Society
  5. "WSe 2 homojunctions and quantum dots created by patterned hydrogenation of epitaxial graphene substrates." Pan, Yi, Stefan Fölsch, Yu-Chuan Lin, Bhakti Jariwala, Joshua A. Robinson, Yifan Nie, K. J. Cho, and Randall M. Feenstra. 2D Materials (2018).

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