Synthesis and electronic properties of Fe2TiO5 epitaxial thin films

Motoki Osada,Kazunori Nishio,Harold Y Hwang,Yasuyuki Hikita

doi:10.1063/1.5025569

Abstract

We investigate the growth phase diagram of pseudobrookite Fe2TiO5 epitaxial thin films on LaAlO3 (001) substrates using pulsed laser deposition. Control of the oxygen partial pressure and temperature during deposition enabled selective stabilization of (100)- and (230)-oriented films. In this regime, we find an optical gap of 2.1 eV and room temperature resistivity in the range of 20–80 Ω cm, which are significantly lower than α-Fe2O3, making Fe2TiO5 potentially an ideal inexpensive visible-light harvesting semiconductor. These results provide a basis to incorporate Fe2TiO5 in oxide heterostructures for photocatalytic and photoelectrochemical applications.

Highlights

Effective use of solar energy for chemical applications, such as photocatalytic and photoelectrochemical fuel generation, is an important current research challenge.1 An essential material component for these processes is the semiconductor which generates the photocarriers, driving the redox reactions at the surface
Development of such photocatalytic semiconductors is focused on simultaneously achieving effective absorption of the solar spectrum, high chemical stability, and controllable electrical transport properties
Its bandgap (3.0–3.2 eV) is large, limiting the effective use of the solar spectrum. α-Fe2O3 with a bandgap of 2.1 eV covering a wider portion of the solar spectrum, together with its low cost and high chemical stability, makes it a promising candidate semiconductor in photocatalytic and photoelectrochemical applications

Summary

Introduction

Effective use of solar energy for chemical applications, such as photocatalytic and photoelectrochemical fuel generation, is an important current research challenge.1 An essential material component for these processes is the semiconductor which generates the photocarriers, driving the redox reactions at the surface. By tuning the substrate temperature and the oxygen partial pressure, we successfully fabricated epitaxial Fe2TiO5 films on LaAlO3 (001).

Results

Conclusion