Molecular Beam Epitaxial Growth and Characterization of Two-Dimensional BN/MoxW1-xSe2 Heterostructures
Abstract
The transition-metal dichalcogenide (TMDC) semiconductors, including MoS2, WS2, MoSe2, WSe2, MoTe2, and WTe2 are indirect bandgap in their bulk case with a crossover to direct bandgap semiconductors in a monolayer limit due to quantum confinement effects. The exciton oscillator strengths in such layer-structured 2Dmaterials are exceptionally large, due to the very large exciton binding energies (0.5 1 eV). Therefore, such emerging 2D materials provide a nearly ideal platform for the exploitation of exciton-polaritons, the mixed states of photon and exciton, to realize room-temperature operational ultralow threshold polariton lasers with phase coherence and intensity stability comparable to that of conventional photon lasers. To date, however, it has remained challenging for the controlled synthesis of 2D TMDC semiconductors and related van der Waals heterostructures with superior quality and clean interfaces. Hexagonal boron nitride (h-BN) is an ideal template for the growth of TMDCs, which can lead to reduced dielectric screening and large exciton binding energy. In this project, we aim to investigate the synthesis and properties of 2D TMDC and BN using molecular beam epitaxy (MBE), the champion semiconductor growth technology which offers ultimate control down to atomic layer in an ultrahigh vacuum environment. We will study the MBE growth and structural and optical properties of 2D TMDCs including WTe2 and WSe2, as well as h-BN. The capacity to epitaxially grow superior quality monolayer TMDC and h-BN by MBE will provide a viable approach for the monolithic integration of various monolayer 2D heterostructures and nanostructures with access to unprecedented material quality, complexity, and degree of control, which is critical for their emerging device applications, including the realization of high temperature polariton lasers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2017
- Accession Number
- AD1059370
Entities
People
- Zetian Mi
Organizations
- University of Michigan