Investigation of the influence of surface treatments on amorphous zinc oxide films, processed at temperatures around 120°C, to control the transport energy levels and charge transport properties (e.g. switch n- to p-type) for the application in photovoltaic-, LED-, and transistor devices on flexible substrates.

Aim of the project is the analysis and evaluation of amorphous ZnO (a-ZnO) and other surface governed ZnO layers, processed at temperatures around 120°C, as a tunable building block in photovoltaic-, electroluminescence-, and transistor devices. The research will cover the following issues:- Analysis of the transport energy levels in intrinsically n-doped a-ZnO thin films, build from ammonium based precursor solution- Post treatment via infiltration and assembling with electron donating and accepting organic adsorbates. Analysis of the possibilities in switching the film properties between isolating, semiconducting, and conducting- Nitrogen p-doping in sulfur anionic substituted a-ZnO with respect to the following issues:-- Passivation of the a-ZnO surface with sulfur to minimize the high density of surface states (comparison to crystalline ZnO (c-ZnO))-- Influence of acceptor migration to the interstitial position and acceptor self compensation, respectively: a-ZnO vs. c-ZnO-- Solubility of the dopant in a-ZnO (comparison c-ZnO)-- Acceptor activation energies in a-ZnO:ZnS in comparison to c-ZnO and dislocations in c-ZnO- Fabrication and characterization of electroluminescent-, photovoltaic, and transistor devices using the tailored a-ZnO layers.

DFG Programme Research Fellowships

International Connection USA

Host Professor Dr. Michael Chabinyc