Photonic device self assembly is a revolutionary manufacturing process with applications in semiconductors, photonics, solid state lighting and photovoltaics. 

NewSouth Innovations (NSi) was awarded one of the first Commercialisation Australia Skills and Knowledge grants early in 2010. The funds were used to hire a consultant in Silicon Valley to engage with informed respondents and potential industry partners and prepare a strategic business plan.

Chip-scale integration of optical components is crucial for a range of technologies as diverse as optical communications, optical interconnects, solid-state lighting, MEMS, biophotonics, displays and photovoltaics. Until now, creation of integrated optical devices was hampered by incompatibilities between materials. Researchers at the University of NSW have developed a method for substrate-independent integration of dissimilar optical components by way of biological recognition-directed assembly.

Bonding in this scheme is achieved by locally modifying the substrate with a protein receptor and the component with a biomolecular ligand, or vice versa; essentially a chemical “Velcro” bonding technique. The high selectivity of the binding of conjugate molecular pairs ensures specific registration of components at the desired location. Vertical-scale assembly of disparate components has also been demonstrated.

Working closely with an industry user group, the team has developed a prototype narrow-band light-emitting device by incorporating II-VI compound quantum dots into silicon based optical resonator. This new hybrid device is assembled on and pumped by a high brightness UV light emitting diode (pictured below).

Biofab enables hitherto impractical operations such as accurate registration of optical components at mass scale, bonding of dissimilar materials, use of polymer substrates, and integration of active components such as light sources and modulators on a common substrate.  Low process temperatures enable the use of new materials. The liquid phase process is cheap, fast, and potentially high volume. Substrates can be patterned with standard lithographic stamps, photoresists or ink jets.

NSi was invited to present at an exhibition of disruptive technologies held in conjunction with the international super computing conference (SC10, New Orleans 2010). As a result, NSi is discussing initiatives with several manufacturing partners in the semiconductor field to evaluate the technology in the assembly of real devices. NSi also intends to seek further funding from Commercialisation Australia for prototype development. 

The below image shows a cross-sectional view of a II-IV quantum dot-doped porous silicon microcavity assembled using bio-recognition on a porous silicon Bragg mirror etched into a silicon substrate. The interface between the reflector components is apparent as a distinct discontinuity at the centre of the structure.