Tampere University of Technology

TUTCRIS Research Portal

Photo-electrochemical and spectroscopic investigation of ALD grown TiO2: Charge transfer characterization and effect of post annealing at different temperature

Research output: Other conference contributionPaper, poster or abstractScientific

Details

Original languageEnglish
Publication statusPublished - 24 Sep 2018
Publication typeNot Eligible
Event30th MAX IV user meeting: Coherent visions - Scandic Star Hotel, Lund, Sweden
Duration: 24 Sep 201826 Sep 2018
https://www.maxiv.lu.se/users/user-meetings/um2018/

Conference

Conference30th MAX IV user meeting
CountrySweden
CityLund
Period24/09/1826/09/18
Internet address

Abstract

Inspired by the photo-electrochemical water oxidation system reported by Fujishima and Honda1, recent work has focused on functionalizing photoactive TiO2 thin films on silicon (Si) semiconductor. Targeting to design an efficient photo-electrochemical device for solar fuel production, finding suitable protection layer material for semiconductors like Si, has recently gained significant attention.

In this work, TiO2 thin films were deposited on highly doped Si substrate by atomic layer deposition (ALD) technique using tetrakis-dimethylamido titanium (TDMAT) and water as a precursors. In order to understand the influence of ALD parameters on TiO2 film performance in photo-electrochemical cell, ALD growth temperature was varied from 150 °C to 225 °C and film thickness from 20 nm to 50 nm. Further efforts were made to analyze the effect of post-annealing treatment in air on ALD films and its influence on photo-electrochemical water oxidation reaction.

The highest applied bias photon-to-current efficiency for Solar Water Splitting (SWS) was obtained in 30 nm ALD TiO2 film grown at 200 °C after post annealing at 475 °C. Annealing at higher temperatures decreased the photo-activity substantially. X-ray photoelectron spectroscopy analysis of TiO2 (2 nm)/Si samples after annealing in air revealed the onset of interfacial SiO2 formation at 450 °C. SiO2 at the TiO2/Si interface act as a charge transfer barrier with detrimental consequence on SWS on TiO2/Si photo-anode.