Charge Carrier Inversion in a Doped Thin Film Organic Semiconductor Island

Inducing an inversion layer in organic semiconductors is a highly nontrivial, but critical, achievement for producing field-effect transistor (OFET) devices, which rely on the generation of inversion, accumulation, and depletion regimes successful operation. In recent years, major milestone was reached: OFET made to successfully operate inversion-mode first time. Here, we develop pulsed bias technique characterize dopant type any material system, without prior knowledge or characterization question. We use this pentacene/PTCDI heterostructure thus deduce that pentacene n-doped by impurities. Additionally, through tip-induced band-bending, generate depletion, accumulation over 20~nm radius, three monolayer thick island. Our findings demonstrate nanometer-scale lateral extent thickness are sufficient device regime.