ZnO_1–x Nanorod Arrays/ZnO Thin Film Bilayer Structure: From Homojunction Diode and High-Performance Memristor to Complementary 1D1R Application

Abstract

We present a ZnO(1-x) nanorod array (NR)/ZnO thin film (TF) bilayer structure synthesized at a low temperature, exhibiting a uniquely rectifying characteristic as a homojunction diode and a resistive switching behavior as memory at different biases. The homojunction diode is due to asymmetric Schottky barriers at interfaces of the Pt/ZnO NRs and the ZnO TF/Pt, respectively. The ZnO(1-x) NRs/ZnO TF bilayer structure also shows an excellent resistive switching behavior, including a reduced operation power and enhanced performances resulting from supplements of confined oxygen vacancies by the ZnO(1-x) NRs for rupture and recovery of conducting filaments inside the ZnO TF layer. A hydrophobic behavior with a contact angle of ~125° can be found on the ZnO(1-x) NRs/ZnO TF bilayer structure, demonstrating a self-cleaning effect. Finally, a successful demonstration of complementary 1D1R configurations can be achieved by simply connecting two identical devices back to back in series, realizing the possibility of a low-temperature all-ZnO-based memory system.

Multilevel resistance in ZnO nanowire memristors enabled by hydrogen annealing treatment

“…[23][24][25][26] Among these, the properties of ZnO have attracted particular interest, due to its wide bandgap, adjustable doping and potential in application in the areas of photodiodes, piezoelectric devices and solar cells. [27][28][29] Many researchers have investigated the memristive behavior of ZnO in various structural motifs, [30][31][32][33] and from which it has been established that the drifts of oxygen ions (or oxygen vacancies) induced by surface treatment can enhance resistive switching in ZnO. 34 Here in this work we investigate the effect of surface modification on the memristive properties of ZnO NWs and demonstrate hysteresis in current-voltage response that is dependent on the history of the device.…”

“…Finally, at sufficiently high voltage (region III), where the electrons fully occupy trap sites, an abrupt surge of current is observed, similar to the formation phenomena reported in numerous resistive switching devices. [4][5][6][7][11][12][13][14][31][32][33][34][36][37][38][39][40][41][42][43][44][45] In the present system, this abrupt turn-on is likely associated with a large local concentration of oxygen vacancies or to the development of a conducting metal (Zn) filaments with the a-ZnO layer. 33 To test the model, we have subjected HAT ZnO devices to different voltage pulse sequences.…”

Emulator Circuits and Resistive Switching Parameters of Memristor

“…Several electrode materials can be used as TE or BE including Pt, Au, Ag, Al, etc. In one diode-one resistor (1D1R)-type memory cell memristor device, one of the electrodes must be a Schottky contact [17].…”

Surface effects of electrode-dependent switching behavior of resistive random-access memory

“…[2][3][4] Among the metal oxides currently being explored to fabricate ReRAM, ZnO has been demonstrated as a potential candidate. ZnO is transparent in the visible spectral region and its electrical properties can be modulated using suitable impurity doping; therefore, it is a promising material for the fully transparent ReRAM which could be used in transparent electronics and displays.…”

“…(1) and (2), we obtain the relations shown in Eqs. (3) and (4). For the SET process, the equation is as follows:…”