Profile 2014 © May 2015 The MacDiarmid Institute for Advanced Materials and Nanotechnology PO Box 600 Wellington New Zealand Email: [email protected] www.macdiarmid.ac.nz ISSN 2324-4461 (Print) ISSN 2324-447X (Online) PROFILE 2014 3 Contents THEME 1 Nanofabrication and Devices 3 THEME 2 Electronic and Optical Materials 24 THEME 3 Molecular Materials 39 THEME 4 Bionano/Nanobio and Soft Matter 62 Outreach Activities 77 Seminar Series 80 Principal Investigators 81 Emeritus Investigators 117 4 THE MACDIARMID INSTITUTE The MacDiarmid Institute FOR ADVANCED MATERIALS AND NANOTECHNOLOGY The MacDiarmid Institute for Advanced Materials and Nanotechnology is a national network of New Zealand’s leading scientists, leveraging strength across the country and internationally. We build materials and devices from atoms and molecules, developing and applying cutting-edge techniques in physics, chemistry and engineering. We capture our diversity to create benefit and build strength. We partner with New Zealand businesses to take our innovative new technologies to export markets in sectors as diverse as health, electronics, food and fashion. We train entrepreneurial and socially- aware young scientists, many of whom go on to work in industry or start their own companies, in a culture of excellence and collaboration. Through sharing the results of our scientific research with the public and with Government, we are inspiring researchers and working to generate a nationwide culture change where science and innovation are celebrated as the keys to New Zealand’s future prosperity. Our Vision Scientific Leadership Excellence Advancement of New Zealand Inspiration PROFILE 2014 5 Our Values 1 Ex Excellence 2 3 Cb Cr Collaboration Creativity 4 5 6 In En Cg Integrity Entrepreneurship Collegiality 7 Our Mission To deliver excellent scientific research Cm and education Commitment Creative, ambitious, innovative research in advanced materials and nanotechnology To forge New Zealand’s future leaders Scientifically astute, entrepreneurial and socially aware leaders To inspire New Zealanders Engendering passion for science and innovation across society To advance a new future for New Zealand The MacDiarmid Institute is a partnership Deliver and support responsible economic development between five Universities and two Crown Research Institutes. Our Investigators are based in Auckland, Palmerston North, Wellington, Christchurch and Dunedin. 6 THE MACDIARMID INSTITUTE THEME 1 Nanofabrication and Devices Personnel University of Otago Principal Investigator University of Auckland Richard Blaikie Principal Investigators Postdoctoral Fellows Cather Simpson, Shaun Hendy Boyang Ding Sam Lowrey Postdoctoral Fellows Bryon Wright, Graham Brodie, Maran Muthiah, PhD Students Michel Niewoudt Levi Bourke Madhuri Kumari PhD Students Noah Hensley Julie Kho, Nina Novikova, Sarah Thompson, Simon Ashforth, Xindi Wang Victoria University of Wellington University of Canterbury Principal Investigators Michele Governale, Natalie Plank, Ulrich Zülicke Principal Investigators Maan Alkaisi, Martin Allen, Simon Brown Postdoctoral Fellows Christina Pöltl, Thomas Kernreiter Associate Investigators Vladimir Golovko, Mark Staiger PhD Students Cameron Dykstra, Conor Burke-Govey, Hani Hatami, Postdoctoral Fellows Hanyue Zheng, Nathaniel Lund, Stephanie Droste Giang Thai Dang*, Isha Mutreja, Shawn Fostner MSc Student PhD Students Luke Pratley, Cameron Wood Alana Hyland, Amalraj Peter Amalthas, Amol Nande, Arunava Banerjee, Baira Donoeva, Daniil Ovoshchnikov, David Anderson, David Kim, Dijana *MacDiarmid Institute funded Bogunovic, Farridah Abu Bakar, Hari Murthy, Ishan Mahajan, Jan Dormanns, Jan-Yves Ruzicka, Jeremias Schuermann, Leila Rajabi, Matheus Vargas, Max Lynam, Mokhtar Mat Salleh, Robert Heinhold, Rodrigo Martinez Gazoni, Rohul Adnan, Salim Elzawi, Sedigheh Ghadamgahi, Senthuran Sivasubramaniam, Vivek Poonthiyill MSc Students Alex Smith, Jacob Martin, Matthew Whiteside GNS Science Principal Investigator Andreas Markwitz PhD Student Prasanth Gupta PROFILE 2014 7 NANOFABRICATION AND DEVICES Report Against Objectives While nanotechnology and the development of advanced materials are tremendously diverse OBJECTIVE 1. topics, fabrication is the key for engineering devices from new materials. Be it at the macroscale, the Sub-wavelength patterning microscale or the nanoscale, the capability to pattern with evanescent interference contacts or add structure to devices must be equally supported alongside materials developments and lithography and high-power theoretical exploration of new device concepts. There femtosecond laser pulses are two approaches to nanofabrication each with strengths and weaknesses. Traditional “top down” methods are critically constrained by resolution (Blaikie, Alkaisi, Simpson) limits, and new approaches are needed. Here we explore such new approaches in areas of optical nanolithography and nano-imprint lithography, and continue to work on atomic- and molecular-scale self-assembly for nanofabrication. We also apply more traditional “bottom up” micro- and nano- MILESTONES ACHIEVED: fabrication techniques to explore electronic, optical • Development of nano-pyramid structures and magnetic materials and devices. Theory and simulation is used to inform and stimulate our for enhanced light harvesting using experimental investigations, and indeed in many Interference Lithography; and cases theoretical predictions drive the direction of the experimental programme. • Determination of the role of Si and Infrastructure and capability: The researchers of Au nanoparticles in light trapping and the MacDiarmid Institute comprise a large fraction absorption in Si solar cells; of New Zealand’s capability in nano-science and technology and the institute’s fertile environment Techniques for manufacturing of nano pyramids on acts as an excellent incubator of ideas and Silicon solar cells were developed and efficient solar interactions. The nanofabrication, microfabrication cells made. A maskless and scalable technique for and processing resources include facilities for growth fabricating nano-scale inverted pyramid structures (PLD, ultra-high vacuum (UHV)-cluster deposition, suitable for light management in crystalline silicon nanowire synthesis), for processing (e-beam, optical solar cells was developed. The technique utilizes and imprint lithography, plasma etching) and finally interference lithography and subsequent combined characterisation (transmission electron microscopy dry and KOH wet pattern transfer etching techniques. (TEM), scanning electron microscopy (SEM), atomic The inverted nanopyramid structures suppress force microscopy (AFM), scanning tunnelling the total reflection at normal incidence to below microscopy (STM) electrical and optical spectroscopy 10% over the entire visible range. The result is that and electronic device characterisation). The laser the overall efficiency of the solar cell has been machining facilities provide access to ‘standard’ increased by 67% with the inverted nanopyramid nanosecond UV laser pulses as well as state-of-the- texturing. Figure 1 shows an example of atomic art femtosecond pulses across the UV/Vis spectrum. force microscope (AFM) of the fabricated pyramid Theory and modelling work is supported by access structures. to high performance computing at NeSI, the National e-Science Infrastructure. Our capital infrastructure is of high quality and, very importantly, maintained and operated by skilled technical support staff. 8 THE MACDIARMID INSTITUTE THEME 1 texturing combined with quantum dot coating could be most promising approach for next generation low cost, high efficiency solar cells. A method was also established to fabricate silicon based solar cells using spin-dopant. A simple but effecient method enabled us to teach solar cells manufacturing to undergraduate students, MacDiarmid Discovery students and Nanocamp participants. MILESTONES ACHIEVED: • Design and build a new robust SILMIL (Solid Immersion Lloyds Mirror Interference Lithography) system demonstrate 50-nm scale patterning though a fibre-based spatially filtered FIGURE 1. An AFM image of inverted nanopyramids. beam; • Perform gap-control experiments using a red-laser based ATR gap control system; • Characterise image quality and depth as a function of gap width using the gap- The work has resulted in both journal publications controlled system; and conference presentations. [Senthuran Sivasubramaniam, Maan M Alkaisi, “Inverted Continuing his near-field lithography system nanopyramid texturing for silicon solar cells development and refinement, Levi Bourke (PhD using interference lithography” 2014/5/1, student) has investigated, implemented and fully Microelectronic Engineering, 119, 146-150, 2014 characterised the fibre-based spatial filter for the and Senthuran Sivasubramaniam, Dhiraj Kumar, Otago SILMIL system. This is now available to use Vladimir Golovko, Maan M Alkaisi “Current alongside the original pinhole-based system, and Density Enhancement in Inverted Nano-pyramid lithography at the 50-nm scale can be achieved with Textured Crystalline Silicon Solar Cell using Gold both setups. Prism redesign has been undertaken Nanoparticles” 12/2013; DOI:10.1117/12.2033731 In by Dr Sam Lowrey (postdoctoral fellow), with new proceeding of: Micro/Nano Materials, Devices, and robust prism cages implemented and a range of Systems, At Melbourne, Victoria, Australia, Volume: optical glasses identified and now in use. The system Proc. SPIE 89232F] design and characterisation