Electrical Conductance and Photoelectric Emission of Thin Bismuth Films

The electrical conductance and photoelectric emission of bismuth films on Pyrex have been simultaneously measured as functions of average film thickness. The films, evaporated always at the rate of 1.11 atom layers ${\min .\mathrm{}}^{-1\mathrm{}}$ in vacuum, were condensed under three different conditions; continuously at liquid-air temperature, discontinuously at room temperature and continuously at room temperature. For all films the conductance and photoelectric emission increase abruptly and nearly together at some film thickness dependent on the temperature of condensation and aging of the film. The agglomeration of mobile condensed atoms satisfactorily explains the results but the process is complex with the condition of the backing surface a likely influencing factor. No photoconductive effect was observed for room temperature or liquid-air temperature deposited films whether aged or unaged. Various experiments on the variation of conductance versus temperature are in agreement with the results of Fukuroi.