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RESEARCH SEMINAR
2nd February 2021: 2.00 pm
Presenter: Benjamin Mbaluka,
Department of Physical Sciences
Title: 'Profiling of surface charge distribution of so-gel derived TiO2 thin films'

Characterization of thermally treated Sol-Gel Synthesized TiO2 Thin Films States by their Surface, Volume Energy Loss and Surface Potential

Benjamin Mbaluka John1,2, Simon Waweru Mugo1 and James Mbiyu Ngaruiya1
1(Department of Physics, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi Kenya)
2(Department of Physical sciences, South Eastern Kenya University (SEKU), Kitui Kenya)

Abstract
We report on variation of optical parameters (Surface and Volume Energy Losses) and surface potential of Sol-gel derived TiO2 thin films prepared at different annealing rates. The Surface Energy Loss and Volume Energy Loss were found to dominate the thin films at low annealing rates (1oC/Min and 2oC/Min), and lowest in the 1-step annealed and the as-deposited thin film. The phenomenon was attributed to the presence of charges traversing the TiO2 films’ surface and increased probability of inter-band transitions with decrease in annealing rate. The change in work function occurred largely due to the introduction of negative ions on the TiO2 films’ surface as the ions induced surface dipole moment. High surface dipole moment resulted into high energy needed for electrons to escape the films’ surface to the vacuum. The results demonstrate a novel model for simple and facile correlation between the optical parameters and surface potential of TiO2 thin films.