Topological insulator Bi2Te3 films synthesized by metal organic chemical vapor deposition

Abstract

Topological insulator (TI) materials such as Bi 2 Te 3 and Bi 2 Se 3 have attracted strong recent interests. Large scale, high quality TI thin films are important for developing TI-based device applications. In this work, structural and electronic properties of Bi 2 Te 3 thin films deposited by metal organic chemical vapor deposition (MOCVD) on GaAs (001) substrates were characterized via X-ray diffraction (XRD), Raman spectroscopy, angle-resolved photoemission spectroscopy (ARPES), and electronic transport measurements. The characteristic topological surface states (SS) with a single Dirac cone have been clearly revealed in the electronic band structure measured by ARPES, confirming the TI nature of the MOCVD Bi 2 Te 3 films. Resistivityand Hall effect measurements have demonstrated relatively high bulk carrier mobility of ~350 cm 2 /Vs at 300K and ~7,400 cm 2 /Vs at 15 K. We have also measured the Seebeck coefficient of the films. Our demonstration of high quality topological insulator films grown by a simple and scalable method is of interests for both fundamental research and practical applications of thermoelectric and TI materials.

Topological Insulator Thin Films and Heterostructures: Epitaxial Growth, Transport, and Magnetism

“…TI films have been grown by a variety of methods. While MBE has been used predominantly, pulsed laser deposition (PLD) [32,33], metal organic vapor deposition (MOCVD) [34][35][36], and vapor liquid solid (VLS) methods, among others, have been used [37]. We now discuss some of the most common materials.…”

Nearly-free-electron system of monolayer Na on the surface of single-crystal HfSe2

“…It directly measures the electronic structure of materials, and can provide valuable information on carrier masses and the interactions between electrons in the system. This has been applied to numerous two-dimensional (or quasi-two-dimensional systems), including surface states of noble metals (e.g., Cu [12,13], Ag and Au [14,15]), semiconductors [16][17][18][19][20], and metal oxides [21,22], and alkali metals grown as two-dimensional layers on metallic substrates [23][24][25][26][27][28]. Despite many of these systems being generally considered weakly interacting, there is hardly any example of a system which displays true nearly-free-electron behavior manifested by a parabolic band dispersion with an effective carrier mass m * = 1m e ).…”

Efficient algorithm to compute the Berry conductivity

“…However, it is much more demanding to control the level of the Fermi energy, which for many samples lies within the bulk energy bands instead of the insulating energy gap, thereby invalidating them as true TIs. This difficulty has motivated the development of sophisticated molecular beam epitaxy (MBE) techniques to precisely control the growth of ultra-thin Bi 2 Se 3 and Bi 2 Te 3 films [14,15]. Likewise, in two-dimensional TIs it is possible to adjust the Fermi energy to lie either in the band gap or the bulk bands.…”