The effect of content and thickness of chitosan thin films on resistive switching characteristics

Abstract

Introduction: Nowadays, a resistive switching memory using biological, transparent, and environmentally friendly materials is appreciated as the tendency of science and technology, especially in the field of electronic devices. Chitosan (CS), having dominant characteristics such as non-toxic, biocompatible and large capacity, plays as a switching medium in resistive random access memory devices (RRAM).
 Methods: In our study, CS film was fabricated onto a commercial substrate (FTO) using a simple spin coating method, and the top electrode (Ag) was deposited by a direct-current sputtering technique.
 Results: The Ag/CS/FTO devices shown the bipolar switching behavior when applying sequence voltage from -1.5 to 2V with the set process in the negative bias and the reset process in the positive bias. The content (0.2, 0.5, and 0.8 wt%) and thickness (100, 300, 500 nm) of chitosan film significantly affect the resistive switching performance. The devices with 0.5 wt%/v concentration and 300 nm-thickness of CS have shown better efficiency than the others with endurance over 100 sweeping cycles and ON/OFF ratio at ca. 2x10 times.
 Conclusions: It is found that the chitosan material has a large potential candidate for applications in optoelectronic devices.

Fabrication and Characterization of Eco-Friendly Thin Films as Potential Optical Absorbers for Efficient Multi-Functional Opto-(Electronic) and Solar Cell Applications

“…As observed in Figure S8b (Supporting Information), all the fabricated devices possess nonideal Schottky diode behavior, since the lowest n-value (~2. 16) was observed for Ag/Cs-NGB/p-Si. The nonideality of the fabricated devices may be rationalized because of the formation of a native oxide layer between Si and the spin-coated chitosan film that develops sufficient series resistance in addition to the hypothetical consequences of the existence of variable heights in the Schottky barrier height (SBH) [12][13][14]38,39,46,50].…”

“…On the other side, chitosan has been exploited in many electronic and optoelectronic applications, such as photodiodes [12], thermal sensors [13], Schottky barrier modifier [13,14], resistive random-access memory (RRAM) [15,16], light-emitting diodes [17], humidity sensors [18,19], modulators [20], and optical waveguides, where the lower-molecular-weight chitosan achieved lower loss than that of the higher molecular weight [21]. Additionally, chitosan possessed unique photochromic features [22] and corrosion inhibition [23].…”

Chitosan–Chitin Nanocrystal Films from Lobster and Spider Crab: Properties and Environmental Sustainability

“…Although the casting of the chitosan/formic acid solution and subsequent drying for 48 h to remove solvent is not preferable for industrial application, this solvent casting approach continues being the major manufacturing approach at laboratory scale. Alternatives to reduce manufacturing time include electrospraying, 42 ionic gelation, 43 spin coating, 44 or exploiting the already existing papermaking procedures. 45 In any case, the solvent casting approach is adequate for fundamental science purposes as it enables the preparation of well-dispersed nanocomposites at low material quantities.…”