Light-controlled manufacturing of semiconductor structures: a platform for next generation processing of photonic devices

This Platform Grant (PG) will apply our internationally-leading expertise in structured illumination and hybrid inorganic/organic semiconductor optoelectronic devices to create new opportunities in the rapidly developing field of light-controlled manufacturing. Structured illumination fields can in principle be obtained from both inorganic (GaN) and organic LEDs, implemented on a macroscale via relay optics, or demagnified to a microscale. Novel manufacturing with photopolymerisable materials can firstly involve use of structured illumination as a novel means to control motorised stages. This technique can be combined with pattern-programmable UV excitation for mask-free photolithographic patterning, continuous photo-curing over larger fields, localised photochemical deposition, or other forms of photo-labile assembly. Process variants can also be envisaged in which arbitrarily positioned fluorescent objects or markers are 'hunted', and then subject to beam excitation for photocuring or targeted photoexcitation. This method could be used, for example, to immobilise individual colloidal quantum dots for use as emitters in quantum technology applications. Multifunctional devices with sensing ability, such as organic lasers for explosives detection, represent another excellent example of automated devices operating under remote conditions. Further examples of the envisaged uses of this technology include:

[1] LED microdisplay asset tags for management of high-value objects (artworks, nuclear fuel containers).
[2] Passive asset tags containing unique micro-patterns of fluorescent objects (eg. colloidal quantum dots, organic macromolecules) for higher-volume, anti-counterfeiting applications.
[3] Customisable continuous-flow micro-reactors for fine chemical manufacturing.
[4] Energy harvesting micro-modules to power other autonomous microsystems, where we will focus on organic PV and ambient-radiation (RF) approaches.

Our work centres on an exciting new approach to the manufacturing of photonic devices that will impact academic and commercial beneficiaries and the public sector. The approach uses arrays of electronically-interfaced light-emitting devices (gallium nitride and organic LEDs, plus hybrids) to generate patterned illumination for a range of coordinated manufacturing functions. These devices provide precision tooling down to the sub-micron level to locate, write on and develop photoresist layers and photosensitive nanocomposites in a directed and spatially localised manner, whilst also controlling mechanically activated multi-step assembly and facilitating process monitoring. Such structured and targeted light is ideal for spatially localised excitation to enable the targeted photo-setting of light-sensitive materials but the same source can also map and identify the area to be illuminated and control the assembly process. This approach does not require a precision mask for patterning of the device and is therefore a highly convenient, low-cost and flexible method for producing a range of differently patterned devices with features down to the micro and nanoscale.

The types of applications we will target range from automated, self-locating systems to hybrid semiconductor devices for visible light communications. The latter includes light fidelity or LiFi, a powerful technology to complement WiFi, which is reaching its limit in terms of data transfer rates with rapidly increasing user demand. Our work will therefore be highly beneficial to the manufacturing sector, end-users in a wide range of businesses (e.g. warehouses, smart lighting for offices and meeting rooms), and the information and communications technology sector. Potential collaborators and beneficiaries include: printing companies that could adopt our manufacturing techniques (Nano Products Ltd., Printed Electronics Ltd., both UK; XCeleprint, Ireland); mask-less lithographic companies (Heidelberg Instruments, Germany); manufacturers of chemical micro-reactors (Little Things Factory, Germany); suppliers of GaN-on-Si LED wafers (Plessey Semiconductors, UK); EPSRC Centre for Innovative Manufacturing in Large Area Electronics, Catapult Centre in High Value Manufacturing.