Executive Summary : | The main aim of this project is to demonstrate ultrafast low-energy electrical switching in memory devices using two-dimensional chalcogenide (2D-Ch) materials. The ultrafast, high storage capacity and energy-efficient data storage are necessary because the current flash memory technology reaches its scaling limit. Due to recent advancements in mobiles, laptops, network-connected devices and the Internet of Things (IoT), the present world shares a tremendous amount of data of about 64 Zettabytes. Thus, there is a demand for a universal memory technology which can able to store, process and transfer such big data efficiently. Chalcogenide materials-based phase change memory (PCM) devices hold great promise for the next-generation data storage technology due to their non-volatility, high scalability, and nanosecond switching time scale. Despite their potential to surpass the present flash technology, which is struggling due to its scaling limit, PCM needs to outsmart the flash memory by its energy consumption and endurance cyclability. Hence, continued efforts are required to address the above issues for the further development of the phase change memory technology. Herein, we aim to study ultrafast electrical switching using various 2D-Ch materials to demonstrate both the ultrafast and energy-efficient switching in the same device. In contrast to the old one-factor-at-a-time, Edisonian method, a highly predictive, time and labour-saving statistical growth method will be employed to grow high-quality chalcogenide crystals such as GeTe, Bi2Se3, Sb2Te3, and Bi2Te3. Various growth parameters such as temperature, pressure, substrate layer, and deposition power will be optimised to develop a recipe for highly c-axis (0 0 L) oriented crystals. These layered structures are then further used to grow 2D superlattice heterostructure by Van der wall epitaxy. This special growth and design of 2D-Ch give extra freedom to tune the phase transition and permit the development of memory devices with better switching speed and efficiency. The high-quality superlattice crystals are further integrated to fabricate prototype memory devices. The T-shaped memory device consisting of a bottom electrode (W), an insulating layer (SiO2), an active medium (SL) and a top electrode (W) will be fabricated to demonstrate the ultrafast switching and energy efficiency. The effect of crystal structure quality and orientation of these superlattice layers will be evaluated to get insights into dimensional confinement of Ge atom which are crucial parameters switching energy efficiency. Therefore, the combination of design, discovery and development of these 2D-Ch materials followed by structural and electrical characterisation will pave a path to understanding the switching mechanism to tailor and tune the device performance. As a result, our ultrafast, energy-efficient memory device can be used for neurotrophic computation, and reconfigurable RF switches. |