Next generation low energy transistors
Monash is developing and patenting new topological 2D materials for use as the next generation transistors. We have developed a method of forming a topological Dirac semimetal layer on a substrate. Using this 2D material we have developed an electric field-effect structure which can be used to alter the charge carrier density and band gap in a topological Dirac semimetal film. In an ultrathin topological Dirac semimetal we can tune the bandgap by over 400 meV, from conventional insulator to topological insulator, realizing a platform suitable for a topological transistor. IBM in 2016 released their 7nm chip. The problem with current technology even though the focus has been on smaller and faster, it is still consuming the same amount of energy. Data centres and server farms are a growing industry. Unfortunately, they now represent 5% of the world energy a significant and rapidly growing source of global emissions. This has been 2020 projected to reach 320 metric tonnes of CO2 per year and is growing >7% per year (faster than any other sector). A further 10% gain in energy efficiency can have a large impact on energy usage and CO2 emissions.
Ultra-thin, focus-tunable and high-speed microlenses for miniaturized optical systems
Microlenses are assuming an increasingly important role in optical devices. With the miniaturisation of optical elements, microlens sizes have correspondingly decreased, and this ‘scaling down’ represents a major problem for focus-tunable systems which require bulky lenses or mechanical components that are difficult to integrate into highly-compact optical devices. We have developed a miniature, focus-tunable, high-speed microlens system suitable for integration into very-compact optical devices. We have established a method to fabricate the world’s thinnest microlens (< 6.3 nm) consisting of a few layers of molybdenum disulphide (MoS2) and have demonstrated that the focus of our microlens can be tuned by an electrical voltage signal, removing the need for bulky mechanical components. Our system can (I) be made on a nano- to micro-metre scale, (II) be electronically tunable using either a metal-oxide-semiconductor (MOS) device or a solid polymer electrolyte-gating device, (III) be tunable at a very high speed (in the range of milli- to nano-seconds), and (IV) have a flexible and transparent polymer substrate. This system is tailorable to specific demands in terms of size, tuning range, transmission range and transmission speed.
Transparent Conducting Oxide Film – Indium Tin Oxide Alternative
Researchers at the University of Minnesota have developed a novel growth approach for the synthesis of doped barium tin stannate (BSO) for use as a transparent conductive oxide (TCO). The material produced has high room-temperature conductivity and mobility when the dopant is lanthanum. The value of conductivity achieved is comparable to that of the best reported value for indium-tin-oxide (ITO), the industry standard for transparent conducting oxide. While other approaches have demonstrated the promise of Lanthanum-doped BSO as a replacement for ITO, these approaches lack reproducibility and the material produced has lower conductivity and transparency. The novel synthesis approach involves using a chemical precursor for tin as a substitute for a solid tin source in a hybrid molecular beam epitaxy system. The advantages include better structural quality of the films, scalable growth rates and high reproducibility. A variety of dopants can be used including lanthanum, neodymium, and gadolinium.