Abstract
In order to elucidate the difference in interface quality between a-Si: H and a-SiN:H layers arising from the order of their deposition, the dependence of photoluminescence efficiency on the thickness of the a-Si: H layer has been studied for three types of specimen structure: a-Si: H/fused silica, a-SiN: H/a-Si: H/fused silica and a-SiN: H/a-Si: H/a-SiN: H/fused silica. Since each type of structure contains a single a-Si: H layer and a combination of different kinds of interface adjacent to it, the defect densities at individual interfaces adjoining the a-Si: H layer can be evaluated separately. The interface between a-SiN: H and a-Si: H when the former is deposited on the latter is of good quality, having a defect density less than 1011 cm−2, whereas interface of the reverse structure contains a higher defect density by about an order of magnitude.