PHOTOCURRENTS THROUGH THIN POLYMER FILMS

Polymer films deposited by electron-beam bombardment were sandwiched between aluminum electrode films. Photocurrents through these sandwiches, with thicknesses between 150 and 300 Å, were measured in the range of photon energies from 2 to 5 eV and with applied voltage bias up to 3 V. The photocurrent vs bias characteristics are symmetrical about the origin. The photocurrent increases with photon energy at fixed bias, with a threshold photon energy of about 2.2 eV, which is independent of the bias. The optical absorption of the polymer shows approximately the same threshold. These results are discussed in terms of the band structure of amorphous semiconductors. © 1969 The American Institute of Physics.