C. Nitschke
Beuth Hochschule für Technik, Master Thesis, 2009

Master thesis 2009

Abstract
In the present thesis electronic and photoelectrical properties of semiconducting titanium dioxide layers were measured using different measuring methods. The titanium dioxide layers had been produced using the sol-gel-process with different precursor solutions. The findings and insights gained shall be used to manipulate the structure and functionality of UV-photodiodes with titanium-dioxide-layers. Traps had been proven both by the analysis of the spectral resolution of the photocurrent and thermally stimulated luminescence. These traps are affected by the titanium dioxide-layer manufacturing process. Using the impedance spectroscopy, the UV-photodiodes inner structure, the width of the space charge layer and the electrical conduction of the titanium dioxide-layer grains and grain boundaries could be measured. Between the impedance of the UV-photodiodes and the speed of reaction a correlation could be noticed. Additionally voltage dependent current and capacity measurements had been carried out as well as thermally stimulated currents had been measured.

Th. Dittrich¹, V. Zinchuk², V. Skryshevsky², I. Urban³, O. Hilt⁴
¹Hahn-Meitner-Institut, Berlin, Germany
²Department of Radiophysics, Taras Shevchenko University, Kyiv, Ukraine
³Bundesanstalt für Materialforschung, Berlin, Germany
⁴sglux GmbH, Berlin, Germany

JOURNAL OF APPLIED PHYSICS 98, 104501 (2005)

Abstract
Pt/TiO₂/Ti Schottky diodes were investigated by current-voltage analysis, photoresponse, and transient photocurrent(PC) in a wide temperature range. The compact TiO₂ as well as the SiO₂ passivation layers were prepared by the sol-gel technique. The Schottky-barrier height (1.2–1.3eV) was equal to the difference of the work functions of Pt and Ti. The temperature dependence of the ideality factor was interpreted in terms of a Gaussian distribution of barrier heights [J. H. Werner and H. H. Güttler, J. Appl. Phys.69, 1522 (1991)]. Space-charge-limited currents under the presence of defects with an exponential distribution were observed. Under zero-potential condition, the PC transients were practically independent of temperature and the electron drift mobility amounted to 2× 10E-4 cm² (Vs)
A screening dipole layer at the Pt/TiO₂ junction was formed under low forward and reverse potentials. Defects were generated under electron injection.