Controlled growth of carbon nanotubes for electronic and photovoltaic applications

Carbon nanotubes (CNTs), experimentally observed for the first time twenty years ago, have triggered an unprecedented research effort, on the account of their astonishing structural, mechanical and electronic properties. Unfortunately, the current inability in predicting the CNTs’ properties and the difficulty in controlling their position on a substrate are often limiting factors for the application of this material in actual devices. This research aims at the creation of specific methodologies for controlled synthesis of CNTs, leading to effectively employ them in various fields of electronics, e.g. photovoltaics. Focused Ion Beam (FIB) patterning of Si surfaces is here proposed as a means for ordering the assembly of vertical-aligned CNTs. With this technique, substrates with specific nano-structured morphologies have been prepared, enabling a high degree of control over CNTs’ position and size. On these nano-structured substrates, the growth of CNTs has been realized by chemical vapor deposition (CVD), i.e. thermal decomposition of hydrocarbon gases over a heated catalyst. The most common materials used as catalysts in CVD are transition metals like Fe and Ni; however, their presence in the CNT products often results in shortcomings for electronic applications, especially for those based on silicon, being the metallic impurities incompatible with very-large-scale integration (VLSI) technology. In the present work the role of Ge dots as an alternative catalysts for CNTs synthesis on Si substrates has been thoroughly assessed, finding a close connection between the catalytic activity of such material and the CVD conditions, which can affect both size and morphology of the dots. Successful CNT growths from Ge dots have been obtained by CVD at temperatures ranging from 750 to 1000°C, with mixtures of acetylene and hydrogen in an argon carrier gas. The morphology of the Si surface is observed to play a crucial role for the outcome of the CNT synthesis: natural (i.e. chemical etching) and artificial (i.e. FIB patterning, nanoindentation) means of altering this morphology in a controlled way have been then explored to optimize the CNTs yield. All the knowledge acquired in this study has been finally applied to synthesize CNTs on transparent conductive electrodes (indium-tin oxide, ITO, coated glasses), for the creation of a new class of anodes for organic photovoltaics. An accurate procedure has been established which guarantees a controlled inclusion of CNTs on ITO films, preserving their optical and electrical properties. By using this set of conditions, a CNTenhanced electrode has been built, contributing to improve the power conversion efficiency of polymeric solar cells.

Why the long face?

In this video, a male voice recites a script comprised entirely of jokes. Words flash on screen in time with the spoken words. Sometimes the two sets of words match, and sometimes they differ. This work examines processes of signification. It emphasizes disruption and disconnection as fundamental and generative operations in making meaning. Extending on post-structural and deconstructionist ideas, this work questions the relationship between written and spoken words. By deliberately confusing the signifying structures of jokes and narratives, it questions the sites and mechanisms of comprehension, humour and signification.

When There's Love

This work is an installation featuring three video projections, music and mirror balls. The three projections fill the walls with scrolling text borrowed from love song lyrics. Headphones in the gallery space allow you to hear a male voice sing the same words to an impromptu tune. Mirror balls send fragments of light spinning around the room while The Righteous Brothers’ Unchained Melody plays on repeat. This work emphasizes fragmentary, repetitious and spatio-temporal experiences of language in order to question the symbolic conventions of romance. By exaggerating and mixing hackneyed symbolic elements, this work extends on some of Nicolas Bourriaud’s theoretical insights into the creative and critical strategies of ‘postproduction’. In particular, it toys with the intersections between popular culture and inter-subjective experiences.

The feeling

In this video, a thumping house-music track is accompanied by lines of rotating text, which resemble computer screen-savers. The text is sourced from websites offering tips for dating and seducing potential lovers. This work engages with the language of online forums. It reworks text from online advice forums and mixes them with visual codes of computer graphics. By extending on some of Nicolas Bourriaud’s ideas around ‘postproduction’ and the creative and critical strategies of ‘editing’, it offers new speculative perspectives on the relationship between screen realities, desire and romance.

Bang

In this video, a male voice performs a script combining stories sourced from an anonymous confessions website. On screen, imagery of fireworks repeats into increasingly kaleidoscopic patterns. This work engages with the relationship between screen culture and contemporary subjectivity. It contrasts private confessions with the public spectacle of fireworks to question the ways screen cultures are informing constructions of subjectivity. By extending on some of Nicolas Bourriaud’s ideas around ‘postproduction’ and the creative and critical strategies of ‘editing’, it offers a speculative understanding of the contemporary tension between public and private.

The way

In this wall-mounted sculpture, a car stereo is mounted into a photographic image of a redwood forest. It plays a sparse and evocative guitar soundtrack. The supporting cabinet is finished with timber veneer to resemble a retro home stereo or piece of designer furniture. This work examines how we construct, represent and deploy notions of nature in our contemporary lives. It mixes the languages of furniture design, landscape photography and sculpture. Drawing on Zygmunt Bauman’s theoretical work on “liquid modernity”, this work questions how and where we find space for contemplation and reflection in a contemporary context increasingly defined by temporary social bonds and consumer choices.

The switch

In this video, text types across the screen one line at a time set to an emotive stock music soundtrack. The text combines two teen film plot descriptions into one story. This work engages with the language of Hollywood narratives. By emphasizing the potentially abstract and convoluted qualities of linguistic communication, it challenges our capacity to assimilate information into conventional narratives. It draws specific attention to the conventions of Hollywood plot development, and questions the mechanisms by which they construct and communicate meaning.

Windows

In this video, words emerge out of an abstract, ‘digital’, animated horizon line. The words are accompanied by a female voice-over who narrates a seductive relaxation and visualization activity. This work examines the nature of consciousness and identity in a contemporary context. It mixes the languages of meditation, new age philosophy and pop-psychology. Drawing on Zygmunt Bauman’s theoretical work on “liquid modernity”, this work questions how and where we find space for contemplation and reflection in a contemporary context increasingly defined by temporary social bonds and consumer choices.

Matter

In this video, an abstract swirling colour-field animation is accompanied by a female voice-over that describes facts and analogies about the earth, the universe and our place in it. This work engages with scientific language and the signifying processes of analogy. It questions the capacity of language to describe epic ideas like the qualities and quantities of the universe and our place in it. By emphasizing the absurdity of describing the scale and formation of the universe through analogies with the ‘everyday’, this work draws attention to the limits of verbal language and its assumed relationship to rational thought.

Peace unknown

In this freestanding sculpture, domestic ‘in-wall’ speakers are mounted in custom-built cabinets. The speakers play a calming stock music soundtrack. The cabinets are faced with photographic mural wallpaper of a stereotypical waterfall scene. This work examines how we construct, represent and deploy notions of nature in our contemporary lives. It mixes the languages of furniture design, landscape photography and sculpture. Drawing on Zygmunt Bauman’s theoretical work on “liquid modernity”, this work questions how and where we find space for contemplation and reflection in a contemporary context increasingly defined by temporary social bonds and consumer choices.

It will be tonight

In this wall-mounted sculpture, speakers are mounted into a shelf-like object finished with timber veneer. The speakers play a corny groove stock music soundtrack. On top of the shelf sits a digital photographic image approximating a fireplace floating against a colour-gradient background. This work examines how we construct, represent and deploy notions of nature in our contemporary lives. It mixes the languages of furniture design, landscape photography, digital graphics and sculpture. Drawing on Zygmunt Bauman’s theoretical work on “liquid modernity”, this work questions how and where we find space for contemplation and reflection in a contemporary context increasingly defined by temporary social bonds and consumer choices.

Particle wave

“Particle Wave” is comprised of six lenticular panels hung in an even, horizontal sequence. Each panel alternates between two solid colour fields as you move past it. There are six colours in total, with each colour represented twice in the spectrum. From left to right, the panels move through yellow, orange, magenta, violet, blue, green and back to yellow. The work’s title refers to the two competing theories of light, which can be understood as either paradoxical or complementary. Like these theories, the experience of viewing the work catches us in a double bind. While we can orient ourselves to see solid colour fields one by one, we are never able to fully capture them all at once. In fact, it is only through our continual movement, and the subsequent transitioning of visible colours that we register the complete spectrum. Through this viewing experience, “Particle Wave” actively engages with our peripheral vision and the transitory nature of perception. It plays with the fundamental pleasures of colour and vision, and the uneasy seduction of being unable to grasp multiple phenomena simultaneously.

Hankering

As a man and woman take turns reciting their favourite simple pleasures, text fades in and out on screen. The visible words, which float against a starscape, are approximations and variations of those being spoken. As the video progresses, the voices and the correlating texts start to overlap slightly. What at first seems to be a testiment to small, saccharine satisfactions starts to become a passive-aggressive race for modest contentment. Rubbing the fine line between sweet and sour, “Hankering” plays with the indirect messages that float through our desires, relationships and the languages we use to communicate them.

Auric Variations

A female voice softly recites physical and psychological associations of aura colours. On screen, individual words fade in and out rhythmically amid a field of swirling and morphing colours. The animated words correlate with the words being spoken, but not every word is displayed, therefore enabling an alternative range of verbal associations to emerge. “Auric Variations” plays with the mix of affirmation and anxiety that can underscore contemporary subjective experiences and the new age techniques we sometimes used to understand them.

Mingling

In this video, white words and phrases fade quickly in and out amongst small bursting dots of colour. Set to an energetic, synthesised soundtrack, the animated text combines, and sometimes confuses, an internal monologue with dialogue and overheard conversations. The unfolding narrative follows an unnamed narrator through a crowded social event. By visually and textually mixing self-conscious reflections with polite conversations, “Mingling” explores the social niceties and nervous behaviours that often inform our interpersonal experiences. Through its fast-paced and disjointed rendering of verbal communication, the work playfully draws out the sometimes-awkward and uncomfortable dialogues that exist between personal and social, internal and external, imagined and actual. This work was commission by the Museum of Contemporary Art, Australia (Sydney), to celebrate the organisation’s major redevelopment and acknowledge the generosity of individuals and organisations who supported the capital project.