Welcome to a guest lecture about solar cells held by associate professor Nobuyuki Matsuki from Kanagawa University in Japan.
Characterization of the near-interface microstructure of a-Si:H/c-Si heterojunction solar cells based on positron annihilation spectroscopy
Nobuyuki Matsuki, associate professor, Department of Electrical, Electronics and Information Engineering, Faculty of Engineering, Kanagawa University, Japan
The power conversion efficiency of amorphous/crystalline silicon (a-Si:H/c-Si) heterojunction solar cell has exceeded 26% recently. Such a high efficiency is essentially achievable thanks to the notable passivation capability of the several-nm-thick amorphous silicon layer deposited on the c-Si surfaces.
For further improvement of the performance it is necessary to understand and to control the structural properties of the a-Si:H/c-Si heterointerface in detail. Recently, we have found that there is a systematic correlation between the microvoid size determined by the positron annihilation spectroscopy (PAS) and the optical constant of a-Si:H by spectroscopic ellipsometry (SE).
Based on this finding, we have established a new characterization methods that allows the average size of micovoid in a-Si:H to be determined using optical measurements. The analysis results obtained by the new characterization method will be discussed.