Rapid Directed Sintering of CdTe/CdS Thin Film Solar Cells Using Intense Pulsed Light

Abstract

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. Atmospheric processing techniques with a high throughput can achieve this. Here we report the use of Intense Pulsed 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. 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. IPL sintering resulted in significant improvement to the crystallinity with processing times of less than 2 minutes.