Hybrid vertical architecture transistor with magnetic-field-dependent current amplification as organic magnetocurrent investigation tool

We prepare hybrid vertical architecture transistors that show magnetic-field-dependent electrical characteristics using tris-(8-hydroxyquinoline) aluminum (Alq(3)), sulfonated polyaniline (SPAN), and n-type silicon. These transistors have n-type silicon as collector, a 200 nm thick SPAN layer as the base, and an emitter composed by Al/Ca/Alq(3) (60 nm) layers, showing permeable-base transistor characteristics. The emitter shows very high magnetocurrent when the Al/Ca is negatively polarized with respect to the SPAN, which is the condition of forward active operation mode. The rate of electrons that cross emitter and base layers and reach the collector is affected by the magnetic field, leading to magnetic-field-dependent common-emitter current gain larger than 1. We also demonstrate that the magnetocurrent is due to the contribution of electrons. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3236574]