Improvement of Boron doping on p-type pm-Si:H thin films for solar cells

Nowadays solar cell industry is in constant search on individual film and interphase enhancement to achieve higher efficiencies even for commercial solar cells. Nevertheless, a reduction of the manufacturing cost and achieving good device quality is desirable for new solar cells development. Pm-Si:H films may be a good candidate due to their improved optoelectronic properties and stability compared to those of the conventional a-Si:H due to their nanocrystalline structure. Several studies revealed that the doping homogeneity of the p and n type films of a solar cell structure may affect the device efficiency, Voc and Isc. Furthermore, an improvement in the lifetimes of such photovoltaic devices is expected to be achieved by increasing the film quality. In such terms, the present work focuses on the study of boron doping on p-type pm-Si:H thin films for solar cells deposited by PECVD. The later study is conducted by means of chemical mapping of the p-type pm-Si:H films at the nanoscale using SEM and EDS simultaneously. The results obtained show a variation in the boron concentration among the films is increased and within the nanocrystals. The significant variation observed may affect the device operation and a change on the deposition parameters showed a decrease. Nevertheless, varying the deposition parameters also affected the nanocrystals size and density, while the boron concentration was increased and almost homogenous within the film.