Formation-free resistive switching in nanocrystalline tellurium oxide

In this work, we report on the observation of resistive switching (RS) in the nanocrystalline tellurium oxide (TeO x ) in ITO/TeO x /Ag device configuration. The TeO x films grown in an O 2 /Ar environment have dominant β -TeO 2 along with other polymorphs and amorphous TeO 2 . From the RS characteristics, it is suggestive that the β -TeO 2 phase promotes the conductive filament formation across the highly insulating amorphous matrix. The memory device demonstrates bipolar RS with excellent endurance, retention and on–off ratio. The device also features formation-free switching with low set and reset voltage (0.6 V and −0.8 V respectively) and displays multilevel switching upon varying compliance current. Current-Voltage characterization clarifies the conduction path is indeed filamentary type. The result highlights that TeO x can be a prominent RS material for memory and brain-inspired computing devices.