Abstract
Amorphous silicon (a-Si) solar cells, which have p-i-n structures, are reviewed with special reference to cell structures and element (φ) additition to a-Si φ: H. The evolution of the structure from singlejunction to multijunction makes tremendous progress in accomplishing higher photovoltaic energy conversion. The high conductivity and transparency of p-layer, or window layer, is of prime importance for the performance of entire solar cells.The improvement of p/i interface is significant in order to avoid recombination of engendered charge carriers migrated from i-layer.Further, hydrogen dilution shows pronounced effect on the reduction of Si dangling bonds which cause recombination.Namely, the photovoltaic efficiency and degradation by light soaking are well ameliorated by these advanced technology.The degraded solar cells contain higher ratio of-(Si-H2)-n dihydride bonding, which is distinguished, by FTIR, from Si-H single bond observed predominantly in initial cells.The formation of dangling bond, recombination of carriers and relationship among Fermi level, band edge, and band width are also discussed. The flexible solar cells fabricated on organic resins have promising future with wide applications.
