Skip to Main Content
We present the first triple junction multibandgap cells incorporating three intrinsic absorber layers that are all deposited by hot wire CVD (Cat-CVD). The bottom and middle cell have a microcrystalline silicon (/spl mu/c-Si:H) absorber layer and the top cell has an amorphous silicon (a-Si:H) intrinsic layer. The cells are made in the configuration stainless steel/n-i-p/n-i-p/n-i-p/ITO and do not comprise a textured back reflector. We obtained a V/sub oc/ of 1.835 V, J/sub sc/ of 7.97 mA/cm/sup 2/, and a fill factor of 0.624. The open circuit voltage is appropriate for this structure, assuming a value of about 0.5 V for the two microcrystalline cells. The fill factor suggests that current matching is achieved, and the high J/sub sc/ shows that there is true spectrum splitting. The triple junction cell, with an efficiency of 9.1%, represents a considerable improvement over our previously presented HWCVD /spl mu/c-Si:H/a-Si:H tandem cells, which had an efficiency of 8.1%. No germanium has been used for this multibandgap cell. The elimination of germane and the use of HWCVD as a fast deposition technique make this triple junction cell concept very attractive for low cost, high efficiency thin film photovoltaic technology.