A new technology for crystalline silicon thin film solar cells on glass based on laser crystallization

A technology is proposed to prepare crystalline silicon thin film solar cells on glass as a superstrate. In a first step an a-Si:H layer is deposited by PECVD onto borosilicate glass. By scanning an Ar⁺ -laser beam, this layer is crystallized with grains several 10 μm in size and is at the same time p⁺-doped by boron from the glass so that a transparent electrode layer is formed. In the next step further a-Si is deposited and repeatedly irradiated by an excimer laser during deposition. In this way, a p-absorber layer is grown epitaxially from the underlying electrode which is acting as a seed layer. Finally, by excimer laser doping, a n⁺-emitter is fabricated to result in a p⁺-p-n⁺-layer sequence. Onto the silicon, a metal is deposited as the second electrode acting as a back reflector. Results on the characterization of the different layers are presented with the emphasis on crystallographic and chemical properties. Challenges in preparing the proposed layer sequence are discussed