DEVELOPMENT OF AGILE TITANIA SENSORS VIA HIGH-TEMPERATURE REDUCTIVE ETCHING PROCESS (HiTREP). PT.1. STRUCTURAL REORGANISATION

• Published in: International journal of applied ceramic technology Vol. 5; no. 5; pp. 480 - 489
• Main Authors: Azad, A-M, Dolan, S, Akbar, S A
• Format: Journal Article
• Language: English
• Published: 01.01.2008
• ISSN: 1546-542X

High selectivity, enhanced sensitivity, short response times and long shelf-life are much sought-after features in solid-state chemical sensors for the detection and metering of gas(es). Because the sensing mechanism of semiconducting oxides is invariably surface dominated, benign microscopic features are desirable to realise a useful sensing material. Such morphological features could be incorporated in a number of semiconducting oxides by using a technique based on thermodynamic consideration of the metal/metal oxide coexistence. By dynamically modulating the equilibrium pO2 across the metal/metal oxide proximity line, renewed formulation and growth of an oxide surface on an atomic/molecular level with exotic morphological features under conditions of oxygen deprivation or enrichment has been achieved in a number of potential ceramic sensor systems. In the case of oxides that are not amenable to such classical oxygen partial pressure modulation, a novel high-temperature reductive etching process (HiTREP) could be exploited to recreate the smart nanofeatures to impart the desired accentuation effect. This surface modification method was applied to a new commercially available aqueous plasma electro-deposited titania thick film, and the microscopic results of this strategy are presented.