In order to get a physical insight into the pentacene interlayer-modulated resistive switching (RS) characteristics, the Au/pentacene/poly(methyl methacrylate) (PMMA)/heavily doped p-type Si (p(+)-Si)/In and Au/PMMA/p(+)-Si/In devices are fabricated and the device performance is provided. The Au/pentacene/PMMA/p(+)-Si/In device shows R-S behavior, whereas the Au/PMMA/p(+)-Si/In device exhibits the set/reset-free hysteresis current-voltage characteristics. The insertion of a pentacene layer is a noticeable contribution to the R-S characteristic. This is because of the occurrence of carrier accumulation/depletion in the pentacene interlayer. The transition from carrier depletion to carrier accumulation (carrier accumulation to carrier depletion) in pentacene occurring under negative (positive) voltage induces the process of set (reset). The switching conduction mechanism is primarily described as space charge limited conduction according to the electrical transport properties measurement. The concept of a pentacene/PMMA heterostructure opens a promising direction for organic memory devices. (C) 2017 Elsevier B.V. All rights reserved.