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HL: Fachverband Halbleiterphysik

HL 90: Phase change / resistive switching (DS with HL)

HL 90.11: Vortrag

Donnerstag, 19. März 2015, 17:45–18:00, H 0111

Reversible Changes Induced by Liquid Electrolyte Gating in the WO₃ Electronic Structure — •Carlos E. ViolBarbosa¹, Julie Karel¹, Simone G. Altendorf², Janos Kiss¹, Yuki Utsumi¹, Mahesh G. Samant², Liu Hao Tjeng¹, Claudia Felser¹, and Stuart S. P. Parkin² — ¹Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany 01187 — ²IBM Almaden Research Center, San Jose, California, USA 95120

Tungsten trioxide (WO₃) is a d0 transition metal oxide that has attracted broad interest due its optical and electrical properties. WO_3−x has a rich phase diagram. Many of the studies in this material make use of modifications in the carrier concentration by chemical doping or creation of oxygen deficiencies. In this work, we utilize ionic liquid electrolyte gating in a electric-double-layer transistor device to induce a metallic state in WO₃ films, a process we will show is reversible.

The modifications in the electronic structure (core levels and valance band) resulting from the gating are probed by hard X-ray photoelectron spectroscopy. Electrolyte gating leads to a significant population of W 5d states in the conduction band and an enormous change in the W 4f core levels. Ab initio density functional theory are used to help describe the origin of these modifications in the electronic structure.