SURFACE STATE AND PERFORMANCE EVALUATION OF SCHOTTKY BARRIER SOLAR CELLS ON AMORPHOUS SILICON.

Large area (75 cm**2) a-Si films were plasma deposited on conducting substrates with a thin heavily doped ohmic contact. Semi-transparent electrodes and contacts were directly evaporated to form MS structurs. MIS structures had an intervening plasma deposited nitride layer. In general, an increased V//o//c with increased phi //m was shown in these n-Si samples. Pd-MIS cells gave V//o//c equals 0. 60v and J//s//c equals 2. 0 ma/cm**2 for cells without an anti-reflection coating. MIS structures gave a 0. 25 v increased V//o//c compared to MS structures. Dark I-V curves exhibited 2 slopes having n-factors ranging from 1. 7 to 4. 0. Surface state density values were in the 10**1**2-10**1**3/cm**2-ev range for MS devices and the 10**1**1-10**12/cm**2-ev range for MIS devices using a continuum model. These values may be compared to 5 multiplied by 10**1**1/cm**2-ev for 12% efficient MIS cells on single crystal Si and 5 multiplied by 10**1**2/cm**2-ev for 8. 8% efficient MIS cells on Wacker polycrystalline Si. Spectral response data indicate an energy gap of 1. 65 ev and need for improved carrier generation and collection.