Biomaterial-Induced Stable Resistive Switching Mechanism in TiO₂ Thin Films: The Role of Active Interstitial Sites/Ions in Minimum Current Leakage and Superior Bioactivity

Abstract

Leakage of current in oxide layers is the main issue for higher speed and denser resistive random-access memory. Defect engineering played a substantial role in meeting this challenge by doping or producing controlled interstitial defects or active sites. These controlled active sites enabled memory cells to form a stable and reproducible conduction filament following an electrochemical metallization model. In this study, a defect-abundant lime peel extract (LPE)-mediated anatase TiO 2 thin film was fabricated using a simple hydrothermal route. The detailed structural and morphological analysis of the bioactive anatase TiO 2 -LPE thin film reveals the homogeneous growth of TiO 2 flowers and distinct features in terms of controlled defects as compared to simple anatase TiO 2 . These interstitial defects (Ti +3 and Ti +4 ) behave as active sites for cation migrations along highly conductive K 1+ ions because of the mediation of LPE. The defect-free surface reveals slight surface roughness (4.8 nm) that successfully minimizes leakage of current. The strategy enabled a reliable conductive bridge filament, which can replicate with no more electric degradation. The Ag/TiO 2 -LPE/FTO-based memory cell demonstrates reproducible bipolar resistive switching along with a high ON/OFF ratio (>10 5 ), excellent endurance (1.5 × 10 3 cycles), and long-term retention (10 5 s) without any electrical degradation. Furthermore, green-synthesized TiO 2 -LPE nanoparticles have shown superior antibacterial activity as compared to other green syntheses of different plants or fruits against the toxic microorganisms present in inorganic media.

Green thin film for stable electrical switching in a low-cost washable memory device: proof of concept

“…4a (cross-sectional view, inset) depicts the uniform 300 nm pectin lm thickness deposited on the FTO substrate. Indeed, the uniform surface morphology along the thickness plays a crucial role in the stability of the conduction lament and avoids undesired current channels 3,16,42 . The thickness-dependent characteristics signicantly enhance the oxygen vacancies.…”

“…23,37,45 Furthermore, surface defects and roughness also play a decisive role in the leakage of the current or undesired current path. 3,16,42 If the number of surface defects and the surface roughness is high, then there is the possibility of the uncontrolled diffusion of the top electrode ions. 46,47 In order to avoid uncontrolled or undesired current channels, the surface roughness should be signicantly minimized.…”

“…In this vein, organic-based devices have aroused research interest owing to their inexpensive manufacturing, low power utilization, pure device fabrication, three-dimensional stacking potential, and multi-state ability for wearable and exible electronics. [1][2][3][4] However, the associated cons of noxious inorganic materials make their practical application challenging. In order to cope with this dilemma, the research community has toiled to explore capable nontoxic biomaterials that are eco-friendly, bioresorbable, biodegradable, biocompatible, and can be easily extracted.…”

“…[5][6][7][8][9][10] Previously, several manufactured optoelectronic devices have been reported using potential biomaterials for write-once and read many times and non-volatile transistor memory applications. [11][12][13][14] Additionally, resistive switching mechanism-based devices have also been fabricated by employing pectin, 15,16 tobacco mosaic virus, 17 ferritin protein, 18 lime peel, 3 2-amino-4,5-imidazoledicarbonitrile (AIDCN) 19 and cysteine. 20 In 2017, for the rst time, Sun et al introduced pectin as a memristor layer that can be degraded in deionized water in 10 minutes, but the high operational voltage needs some improvement.…”

“…21,22 Moreover, surface roughness also plays a decisive role in preventing undesired current paths that may lead to unstable conduction laments and high operational voltage. 3 In this contribution, various in situ experiments were carried out to minimize current leakage or prevent undesired current paths via surface defect engineering and the introduction of localized point defects within the insulating layer. These point defects act like a hopping charge carrier, minimize the leakage factor and provide a smooth tunable conductive path.…”