Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 94: Poster IV A (Laser; Devices; Heterostructures; Surfaces, interfaces and defects)
HL 94.12: Poster
Thursday, March 19, 2015, 14:00–20:00, Poster B
Deep level transient spectroscopy of hydrogen-generated traps in nanoporous titanium dioxide — •Laurin Schnorr1, Mihai Cerchez1, Thomas Heinzel1, and Dieter Ostermann2 — 1Solid State Physics Laboratory (IPkM), Heinrich-Heine-Universität Düsseldorf, 40204 Düsseldorf, Germany — 2ODB-Tec GmbH & Co. KG, Bussardweg 12, 41468 Neuss, Germany
Deep level transient spectroscopy was carried out on Pt / nanoporous TiO2 Schottky diode hydrogen sensors to investigate whether in addition to a shallow donor level deep traps get formed during hydrogen exposure. Therefore the sensor was exposed to different doses of molecular hydrogen using a H2 in N2 gas mixture with hydrogen concentrations in the ppm regime to allow time resolved measurements. A defined initial state of the sensor was achieved by exposing it to dry air at hight temperatures until the current-voltage characteristics became purely diodic. The DLTS measurements revealed two hydrogen-independent deep levels at 0.4eV and 0.6eV below the bottom of the conduction band. A third level at about 0.6eV with a significantly smaller emission rate could only be observed after exposures to high doses of H2 and was reversible by oxygen exposure, suggesting that this level is related to hydrogen atoms interacting with oxygen vacancies.