Transient response of photocurrent multiplication phenomenon at organic/metal interface was revealed to have two components, which were identified as primary and subsequent multiplied photocurrents, respectively. Transient photocurrent directly traced the multiplication process, i.e., accumulation of photogenerated carriers near the interface, building up a high electric field at the interface, and tunneling electron injection from metal electrode to the organic layer. Amount of charges required for the multiplication onset was found to give a specific value of 30 nCcm−2, implying that the increase of the carrier generation efficiency of primary photocurrent is expected to be effective to realize high speed multiplication. Based on these results, we developed the double-layered device which can be driven in high voltage through the increase of film uniformity. Consequently, large multiplication rate of 1.7 x 105 and short response time of 3.7 s was achieved.
Ken-ichi Nakayama, Masahiro Hiramoto, Masaaki Yokoyama, "Transient Response of Multiplied Photocurrent Observed in Metal/Organic Pigment Film Interface" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP14), 1998, pp 490 - 493, https://doi.org/10.2352/ISSN.2169-4451.1998.14.1.art00039_2