Bipolar resistive switching and memristive properties of hydrothermally synthesized TiO2 nanorod array: Effect of growth temperature

Abstract

In the present work, the hydrothermal approach is employed to develop 1D-TiO2 nanorod array memristive devices and studied the effect of hydrothermal growth temperature on TiO2 memristive devices. X-ray diffraction (XRD) analysis suggested that the rutile phase is dominant in the developed TiO2 nanorod array. Field emission scanning electron microscopy (FESEM) images show well adherent and pinhole free one dimensional (1D) TiO2 nanorods. The presence of titanium and oxygen in all the samples was confirmed by energy dispersive X-ray spectroscopy (EDS). Furthermore, growth of the 1D TiO2 nanorods depends on the growth temperature and uniform growth is observed at the higher growth temperatures. The well-known memristive hysteresis loop is observed in the TiO2 nanorod thin films. Furthermore, resistive switching voltages, the shape of I-V loops and (non)rectifying behavior changed as the growth temperature varied from 140 o C to 170 o C. The biological synapse properties such as paired-pulse facilitation and shortterm depression are observed in some devices. The detailed electrical characterizations suggested that the developed devices show doubled valued charge-magnetic flux characteristic and charge transportation is due to the Ohmic and space charge limited current.

Metastable oxygen vacancy ordering state and improved memristive behavior in TiO2 crystals

“…The notably pinched I-V hys- teresis loops, as shown in Fig. 5a, demonstrate the perfect memristive effect at temperatures close to the V O ordering temperature [36][37][38]. The memristive effect occurred at a very low field on the order of~10 V/cm, which rivals all known thin film memristors in which the memristive effect requires a large DC electric field on the order of 10 3 -10 6 V/cm even at high temperatures [39].…”

Coexistence of filamentary and homogeneous resistive switching with memristive and meminductive memory effects in Al/MnO2/SS thin film metal–insulator–metal device

“…On the other hand, the filamentary RS suffers from scaling issues [1,11]. The synergetic integration of homogeneous and filamentary RS may lead to highly scalable and efficient memory cells that would be useful for the CMOS-compatible RRAM and neuromorphic applications [15][16][17][18][19]. Considering the advantages of synergetic integration, many research groups come up with different solutions.…”

Influence of Growth Temperature on TiO2 Nanostructures by Hydrothermal Synthesis

“…The oxygen content is slightly decreases as the growth temperature increases. This finding may attribute to the out-diffusion oxygen that occurred at moderate and high temperature [33]. No element of SnO is detected at moderate and high temperature slightly different from XRD result due to the compactness of TiO 2 nanorods/nanoflowers area during the EDS detection.…”

“…where  h is the photon energy,  is the absorption coefficient, E g is the absorption band gap, A is constant, n depends on the nature of the transitions, and may have values ½, 2, 2/3 and 3 corresponding to allowed indirect, allowed direct, forbidden direct and forbidden indirect transitions of band gap respectively. In this case, n = ½ is chosen for indirect allowed transition [33]. The absorption band edges were estimated around 400 nm slightly higher than normally reported of λ = 388 nm TiO 2 .…”