A chitosan based ReRAM for green computing
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Authors
Giba, Khanya
Issue Date
2024-11-19
Type
Dissertation
Language
en
Keywords
Chitosan , PVP , CdTe/CdSe , ReRAM , Green memory , Fourth Industrial Revolution and Digitalisation , SDG 9 Industry, Innovation and Infrastructure , Natural Sciences (Biotechnological studies)
Alternative Title
Abstract
The utilization of information technology (IT) has witnessed a significant surge in recent years, as businesses heavily depends on IT systems for a multitude of operations, including communication, data storage, and customer management. This trend is likely to persist as technology advances and becomes increasingly integrated into everyday business operations. Furthermore, there exists a clear inverse correlation between the quantity of emerging information technology and its longevity. It is obvious that newer, more sophisticated systems are replacing older ones quickly on a daily basis. This, in turn, contributes to the rapid increase in electronic waste, which is considered a significant environmental hazard because of the toxic materials present in electronic devices. It is important to recognize that memory devices play a crucial role in information technology. There is a clear demand for memory devices to progress in terms of their sophistication and efficiency. Memory devices are essential for storing programs or applications required to carry out various tasks. With the constant advancement of technology, the need for powerful memory devices is only set to increase. Flash memory, dynamic random-access memory (DRAM), and static random-access memory (SRAM) face significant challenges in terms of speed, capacity, and energy efficiency. Researchers are continuously striving to create innovative technologies that can overcome these challenges and enhance the performance of memory devices. Examples of such technologies include resistive random-access memory (ReRAM) and phase-change memory (PCM). These advancements have the potential to revolutionize electronic devices and contribute to a more sustainable future by increasing product longevity and reducing electronic waste. In this study, a ReRAM device with a sandwich-type configuration was fabricated and analyzed for its memory capability. The device consists of an active layer sandwiched between a bottom electrode and a top electrode. This device has a notation: Ag/CS+PVP+CdTe/CdSe/ITO. The active layer, also known as the resistive switching layer, was made up of chitosan (CS) and polyvinylpyrrolidone (PVP), which were both biodegradable materials. These were mixed with CdTe/CdSe core-shell quantum dots. Contrastingly, the top electrode consisted of silver (Ag), while the bottom electrode was comprised of an indium-doped tin oxide (ITO) layer. This memory device was developed on a polyethylene terephthalate (PET) substrate. When voltage was applied between the Ag and ITO electrodes, current in the Ag/CS+PVP+CdTe/CdSE/ITO device was measured, and some fascinating discoveries were made. The device demonstrated memory hysteresis, with a satisfactory ION/IOFF ratio of ≥ 10 and a low working voltage of ≥ 0.2 V. Based on these observations, it appears that the device operates as a memory device while consuming very little power. In addition, it was suggested that the addition of CdTe/CdSe to the composite material could increase the Schottky barrier height at the interface between the electrodes and the active layer, thereby preventing electrons from entering the active layer. Conductive filaments were consequently formed because of the diffusion of Ag+ ions into the active layer. Considering the study's results, it appears that incorporating CdTe/CdSe QDs could enhance the memory and switching capabilities of the CS/PVP blend-based resistive switching memory.