Dr Avi Braun is a Research Associate in the Faculty of Natural Sciences, Department of Physics at Imperial College, London. Located in the Blackett Laboratory, Dr Braun joined the Quantum photovoltaic group in December 2013 as an Imperial College Junior Research Fellow. His main subject of research is the harnessing and integration of nano-photonic structures with photovoltaic and other opto-electronic and sensing applications. This research involves the design, simulation, fabrication and characterization of miniaturized opto-electronicdevices and plasmonic sensors.

Dr Braun uses the Quorum Technologies Q150T coater to deposit a variety of metals and ITO (indium-tin oxide) to make plasmonic sensors and electric contact pads. Describing what he particularly likes about the Q150T, Dr Braun says “In comparison with more sophisticated high vacuum systems, the Q150T is much faster thus allowing us to have a fast prototyping and development process.It is also very simple to use; this enables us to give students access to the system as part of their academic practical training. The metals we use include gold, silver, ITO and a nickel-copper alloy. These we deposit in a thickness range of 50-150 nm. We also put down adhesion layers of chromium and titanium to a thickness of 3-5 µm. We particularly like the way we are able to change targets – fast and simple. We also find the angled rotational stage very good for coating 3D structures.”

Dr Braun and his colleague, Professor Stefan Maier, have published work in ACS Sensors. Itdescribes the fabrication of plasmonic IR sensors using direct laser writing and metal deposition using the Q150T system. Entitled “Versatile direct laser writing lithography technique for surface enhanced infrared spectroscopy sensors”, the paper is available online through the American Chemical Society at ACS Sens., 2016, 1 (9), pp 1155–1162, DOI: 10.1021/acssensors.6b00469.

Dr Elisabeth (Beth) Steer is Specimen Preparation Technician at the Nanoscale and Microscale Research Centre, (NMRC), in the Faculty of Science at the University of Nottingham. The Centre is a cross-faculty hub providing facilities and expertise for research across the engineering, physical and life sciences. The Centre is well placed and ready to support academics in achieving excellence in their research and leveraging the funding available in nanoscience and related interdisciplinary areas. It is proud host to a unique suite of over twenty instruments which facilitate the imaging and analytical investigation of materials from a wide range of scientific disciplines. The NMRC also welcomes commercial and industrial access making it one of the most versatile imaging centres in the country.

Beth’s work covers many different preparation processes. These include sputter coating, evaporation coating, critical point drying, resin embedding, microtomy & ultramicrotomy, polishing and grinding. The key to successful coating performance is reproducibility. Beth takes up the story: “We use the Quorum 150T S turbomolecular-pumped system to sputter coat samples with iridium here prior to analysis on a JEOL 7100 FEG-SEM. The iridium coating is essential as the other types of coating we have here (Pt, Au) have a grain size too large for use with the FEG as the structure of the coat covers nano features we’re trying to observe. When working on a nanoscale, it’s very important to have an even coat covering the samples that is reproducible. We tend to coat between 5-15 nm.”

Continuing, she says “Compared to our other coaters, the Q150T has a very controllable, easily reproducible coat – helped by the turbo pump. The reproducibility is very important to us as if we coat a sample with something that varies by a few nm then the sample is difficult to interpret and once we find a thickness that works for a sample type we need to be able to reproduce it to 1 nm. Film thickness is very important for us. It varies with every sample type, but we find the ability to produce coats <5 nm essential for FEG work and that isn’t really possible without a Film Thickness Monitor.”

Sales Manager, Dennis Fitzpatrick, says “Quorum offers the most versatile range of sputter and carbon coaters for electron microscopy today. The Q150T is available in three formats: sputtering, carbon evaporation or both. Depending upon the selected configuration, the Q150T can be a top-of-the-range sputter coater for high resolution scanning electron microscopy (SEM), a carbon coater suitable for SEM and transmission electron microscopy (TEM), or both – in a single easy-to-use system. Other options include metal evaporation and aperture cleaning.”

Shaun Graham is part of the applications development team at Carl Zeiss Microscopy based in Cambridge. With a Masters in applied and environmental geology, he works in the geosciences, mining and oil & gas sectors to provide analytical solutions using scanning electron microscopy performed on mineral samples. This includes the provision of sample preparation equipment including a turbo-pumped coater from Quorum Technologies.

One of the main applications of the geosciences business, with its automated mineralogy software, is to provide data on mineral processing plant products from mining companies. It is vital that operating mines are able to track mineralogical and textural variation for processing and recovery optimizations. Recognising variability can save or make huge amounts of money to a company by maximizing yield and quality. The instrumentation has to be rugged and extremely reliable as it will often be located at the mine site itself. This has to be easy-to-use. Operators are not qualified scientists. They just require quick, accurate and actionable data to make informed decisions.

ZEISS supplies a special dedicated package to deliver to these requirements. This comprises sample preparation equipment and a “ruggedized” SEM. The system, known as MinSCAN, has been designed for this challenging environment, a mine-site mineralogy laboratory on wheels! A powerful data system takes the results to enable an increase in profits through greater concentrate quality and reduced losses to tailings (the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore.). Being able to rapidly troubleshoot recovery issues, optimize plant performance and complement assays gives metallurgists, mine managers and superintendents the confidence to make effective decisions based on reliable, quantitative data.

Key to reproducible sample preparation is a Quorum Q150T providing high resolution carbon and sputter coating. Each 30 mm standard sample requires reproducible, uniform, thin coatings. Carbon coating is used in perhaps 80% of the applications where mineral particles are being investigated. For oil and gas applications, the ability of having a thin coating becomes most important when making porosity measurements. Uniform thinness will greatly reduce imaging artefacts. As Shaun says about the selection of Quorum coaters, “the Q150 series has been chosen based on its proven extremely reliable performance in what is usually a difficult environment far removed from the traditional research bench. The coater has to be available 24/7 as the failure to be able to coat a complete batch of daily samples in a day will risk loss of profit through the lack of actionable data from that days production. This is so important to our users that ZEISS supply, install and train users on all elements of the experimental process.”

Technical Director, Bob Morrison, says “Quorum has a long established track record as the preferred supplier of coaters for mining applications. Reliability is extremely important in these situations and we have been able to demonstrate the reliability and performance of the Q150T coater in our dealing with partners like Zeiss over a number of years.” The Q150T is available in three formats: sputtering, carbon evaporation or both. Depending upon the selected configuration, the Q150T can be a top-of-the-range sputter coater for high resolution scanning electron microscopy (SEM), a carbon coater suitable for SEM and transmission electron microscopy (TEM), or both – in a single easy-to-use system. Other options include metal evaporation and aperture cleaning.