intense pulsed light, sintering, CdS, CdTe
Thin film solar cells typically require post-growth heat treatment to improve the materials properties. In order to manufacture market competitive solar cells, material processing methods with low capital and running costs are required. One method for achieving this goal would be to use atmospheric processing techniques with a high throughput. Here we report the use of Intense Pulse Light (IPL) to process cadmium sulfide (CdS) and cadmium telluride (CdTe) thin films. IPL is an ultra-fast technique for the heat treatment of materials. Pulses of light from the UV to IR wavelengths are absorbed by the material, leading to localized heating and sintering. IPL has been used to successfully make Cu electrical contacts for use in electronic circuits, however little work exists on the use of IPL in the processing of semiconductor materials. The effect of energy input and the energy density (ED) of the pulse on the films optical, compositional and morphological properties of the films were investigated using UV-Vis spectroscopy, X-ray diffraction, photoluminescence and scanning electron microscopy. These analytical results are supported by computational analysis of the thermal response within the films. IPL sintering resulted in significant improvement to the crystallinity with processing less than 2 minutes.