Resistive Switching in p-Type Nickel Oxide/n-Type Indium Gallium Zinc Oxide Thin Film Heterojunction Structure

Abstract

We report a p-type nickel oxide/n-type indium gallium zinc oxide (p-NiO/n-IGZO) thin film heterojunction structure for resistive switching memory application. The as-fabricated structure exhibits the normal p-n junction behaviors with good rectification characteristic. The structure is turned into a bipolar resistive switching memory by a forming process in which the p-n junction is reversely biased. The device shows good memory performances; and it has the capability of multibit storage, which can be realized by controlling the compliance current or reset stop voltage during the switching operation. The mechanisms for both the forming process and bipolar resistive switching are discussed; and the current conduction at the low- and high-resistance states are examined in terms of temperature dependence of the current-voltage characteristic of the structure.

Mechanism of Nonvolatile Resistive Switching in ZnO/α-Fe2O3 Core–Shell Heterojunction Nanorod Arrays

“…The ON/OFF ratio is found to be ∼20 at an applied reverse bias of −0.55 V, large enough for meeting requirements for practical memory applications. 22,23 As the top-probe/α-Fe 2 O 3 /bottom-probe and top-probe/ ZnO/bottom-probe contacts show ohmic I−V characteristics in electrical transport (shown in Figure S2, Supporting Information), therefore, such unique bistable resistive switching as demonstrated above for this heterojunction NRs, can only be attributed to arise from the ZnO/α-Fe 2 O 3 heterojunction interface. Particularly, reversible migration of ionized defects, like charged oxygen vacancies (V O + ), chemisorbed oxygen ions (O x ads − ) under the electrical or thermal influence have been found to be responsible behind the resistive switching mechanism in many other heterojunction devices.…”

“…When the voltage crosses ∼−0.55 V, a sudden increase in current reaching the compliance level could be observed, thus setting the device into the low-resistance state (LRS) or “ON” state. The ON/OFF ratio is found to be ∼20 at an applied reverse bias of −0.55 V, large enough for meeting requirements for practical memory applications. , …”