Work

Atomically-smooth single-crystalline VO2 (101) thin films with sharp metal-insulator transition

Year: 2019

Type: article

Abstract: Atomically-abrupt interfaces in transition metal oxide (TMO) heterostructures could host a variety of exotic condensed matter phases that may not be found in the bulk materials at equilibrium. A critical step in the development of such atomically-sharp interfaces is the deposition of atomically-smooth TMO thin films. Optimized deposition conditions exist for the growth of perovskite oxides. However, the deposition of rutile oxides, such as VO2, with atomic-layer precision has been challenging. In this work, we used pulsed laser deposition to grow atomically-smooth VO2 thin films on rutile TiO2 (101) substrates. We show that an optimal substrate preparation procedure followed by the deposition of VO2 films at a temperature conducive for step-flow growth mode is essential for achieving atomically-smooth VO2 films. The films deposited at optimal substrate temperatures show a step and terrace structure of the underlying TiO2 substrate. At lower deposition temperatures, there is a transition to a mixed growth mode comprised of island growth and layer-by-layer growth modes. VO2 films deposited at optimal substrate temperatures undergo a sharp metal to insulator transition, similar to that observed in bulk VO2, but at a transition temperature of ∼325K with ∼103 times increase in resistance.

Source: Journal of Applied Physics

DOI: 10.1063/1.5124106

Authors: Debasish Mondal, Smruti Rekha Mahapatra, Tanweer Ahmed, Suresh Kumar Podapangi, Arindam Ghosh, Naga Phani B. Aetukuri

Institution: Indian Institute of Science Bangalore

Language: English

Topic: Transition Metal Oxide Nanomaterials

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: Indian Institute of Science, Department of Science and Technology, Ministry of Science and Technology, India

Awards: G1413321961, G1482810890