A New Approach to the Fabrication of Memristive Neuromorphic Devices: Compositionally Graded Films

Abstract

Energy-efficient computing paradigms beyond conventional von-Neumann architecture, such as neuromorphic computing, require novel devices that enable information storage at nanoscale in an analogue way and in-memory computing. Memristive devices with long-/short-term synaptic plasticity are expected to provide a more capable neuromorphic system compared to traditional Si-based complementary metal-oxide-semiconductor circuits. Here, compositionally graded oxide films of Al-doped MgxZn1−xO (g-Al:MgZnO) are studied to fabricate a memristive device, in which the composition of the film changes continuously through the film thickness. Compositional grading in the films should give rise to asymmetry of Schottky barrier heights at the film-electrode interfaces. The g-Al:MgZnO films are grown by using aerosol-assisted chemical vapor deposition. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the films show self-rectifying memristive behaviors which are dependent on maximum applied voltage and repeated application of electrical pulses. Endurance and retention performance tests of the device show stable bipolar resistance switching (BRS) with a short-term memory effect. The short-term memory effects are ascribed to the thermally activated release of the trapped electrons near/at the g-Al:MgZnO film-electrode interface of the device. The volatile resistive switching can be used as a potential selector device in a crossbar memory array and a short-term synapse in neuromorphic computing.

Direct Integration of Monolayer WS2 with Lithographically Patterned Carbon Contacts for Memristor Application

“…It is worth mentioning that this kind of phenomenon has been reported previously for binary oxides and perovskite materials, but it has not been explored much in 2D materials. 37,38 The I−V curves show the counterclockwise direction of hysteresis behavior, and at low voltages, the device shows a high resistance state (HRS) with a small memory window. The increase in memory window and increase in low resistance state (LRS) current take place with an increase in voltage.…”

Nanoscale mapping of temperature-dependent conduction in an epitaxial VO2 film grown on an Al2O3 substrate

“…The 20 nm-thick VO 2 film was deposited on the c -Al 2 O 3 substrate by using aerosol-assisted chemical vapor deposition. 33 A precursor solution of 0.01 M concentration was prepared by dissolving vanadyl acetylacetonate (the source material for V ion) in 2-methoxyethanol. An aerosol of the precursor solutions was ultrasonically produced in a glass vessel and transported with Ar carrier-gas to a reaction chamber in which pyrolysis of the chemical vapor occurred on a heated substrate to produce a solid film.…”