title: Phase Equilibrium in Cd-Te-O-Cl Systems and Development of PV Solar Cell Materials
reg no: ETF5604
project type: Estonian Science Foundation research grant
subject: 1.6-1.9. Chemistry and Molecular Biology
2.2. Materials Science
status: accepted
institution: TTU Faculty of Mechanical Engineering
head of project: Jaan Hiie
duration: 01.01.2003 - 31.12.2006
description: Investigation of vapor-liquid-solid equilibrium in the systems of CdTe with CdCl2 and native oxides and influence of Cd and Te2 partial vapor pressures on the composition of the equilibrium phases. Experimental methods: DTA, DSC, XRD, chemical analysis and measurement of physical properties of liquid and solid phases.
Solidus and liquidus data on the melting points and concentrations of the components in the equilibrium phases makes possible: (1) to handle more precisely the present industrial CdTe:CdCl2:O2 annealing process, widely used in the production of CdS/CdTe solar cells for improvement of their characteristics and (2) to elaborate a new method for liquid phase epitaxy of CdTe through conversion of native oxides in the melted solution with CdCl2 to the CdTe solid phase under the influence of H2 and Te2 gas phase in a temperature gradient.
Expectable results.
Any ultimate goals of the work are the CdTe solar cells with significantly improved efficiency and technological methods to reach them.
Physico-chemical data on the phase diagrams of CdTe with CdCl2 and native oxides are important as a valuable basic technical and scientific information especially in the field of PV solar energy materials.
Preparation of test samples of PV layers, PV solar cells and solutions of technical problems (patent application materials, applications for utility patents, exhibition materials).

project group
no name institution position  
1.Jaan HiieTTU Faculty of Mechanical EngineeringSen. Res. Scientist 
2.Andres TaklajaTallinn Technical UniversityProfessor 
3.Vello ValdnaTallinn Technical UniversitySen. Res. Scientist