The further development of cadmium telluride and cadmium sulphide thin film PV cells.
Being a direct band semiconductor with a room temperature energy gap of 1.5 eV., CdTe is a promising photovoltaic material particularily suited for thin film devices. Several workers now report the formation of CdTe thin films on tinoxide coated glass by solution growth techniques. Such films predominately show a sphalerite structure and p type conduction with resistivity around 2 * 105 W/cm2
Cadmium sulphide thin firms have been prepared by this school for some years. The films are prepared by the spray pyrolisis of cadmium chloride and thiourea, and typically 20 m thick have dark resistivities of 22cm. As CdS is a known n type semiconductor, the p-n junction between CdS and CdTe may well be worth investigating for its photovoltaic properties.
Tasks will be allocated as follows :
NEWCASTLE POLYTECHNIC - will grow the CdTe films. (For health and safety reasons, this would not be possible in a school laboratory.)
TWYFORD CE HIGH SCHOOL - will be responsible for the electrical characterisation of the CdTe films, the growth of the n type CdS layer and its characterisation together with initial efficiency measurements of the resulting cell.
FRANK WHELDON SCHOOL, NOTTINGHAM - will co-ordinate the work of the French and German partners through its current exchange scheme.
C.E.S. JAN HAY, MORRENNES - will undertake life time tests and thermal cycling tests on the resultant cells.
SCHILLER GYMNASIUM, COLOGNE - will investigate the spectral response of the CdS-CdTe cells, together with their output as a function of irradiance.