Hybrid microcavity light emitting devices by additive manufacturing

Lead Research Organisation: University of Sheffield
Department Name: Electronic and Electrical Engineering

Abstract

This project seeks to develop new and more efficient light emitting optoelectronic devices such as LEDs, with emission wavelengths tuneable over the visible spectrum including the current gaps in green and yellow. In order to achieve this, optical microcavity devices will be fabricated with semiconductor materials suspended between mirrors to make use of so called 'strong coupling' effects, bringing two different classes of semiconductor materials together in precisely controlled micro-structures the same size as the wavelength of light. Work will focus on combining gallium nitride based semiconductor materials and other families of semiconductor materials such as colloidal quantum dots and light emitting polymers in optical micro-cavity structures leading to potentially higher efficiency LEDs and lasers in the future.

While the study of these coupling effects has previously required specialist and one-off fabrication approaches in laboratory conditions, this project aims to develop and employ manufacturing capable large scale processes to create these hybrid microcavity LEDs. New techniques will be developed to remove III-nitride LEDs from their growth wafers before employing the additive manufacturing process of transfer printing. This will be used to build hybrid material microcavities by stacking optimized complimentary materials together in a precisely controlled manner. Bringing these different materials together by additive manufacturing allows optimized, high efficiency components to be combined without compromises normally required due to the different processing temperatures and environments for different materials systems.

Planned Impact

Hybrid microcavity devices and the manufacturing compatible processes developed to enable them have the potential to impact across a range of areas spanning knowledge, economy, people and society.

Economy: The UK has a large and significant photonics industry (£13bn) and is currently seeing significant investment in the field of compound semiconductor device manufacture. Through the development of new manufacturing processes enabling new and more efficient optoelectronic devices, UK industry stands to benefit through developing and exploiting new IP and developing processes that make use of the UK compound semiconductor supply chain such as cadmium free quantum dots.

Knowledge: Through developing and disseminating the technology and scientific findings resulting from this work, there are a range of potential academic beneficiaries (detailed above). This will have an impact on UK and international research, helping progress the directly related field of hybrid semiconductor materials and devices but also in related areas through providing a platform for the study of polariton effects in a range of materials and in enabling manufacturing compatible fabrication approaches in the field of GaN materials and devices.

People: The UK photonics industry is currently expanding at 5% per anum, the compound semiconductor supply chain is seeing massive investment and as such there is a need for a large number of highly skilled people to work in these industries. Through this work a PDRA will be trained and gain experience useful to the UK photonics and compound semiconductor industries. Indirectly, PhD students under the supervision of the PI will benefit from working on related areas, providing a good base for future work in or with the photonics and compound semiconductor industries.

Society: A longer term impact of the work proposed here is as a result of the potential new optoelectronic devices following on from this work such as coherent light sources at new wavelengths and flexible light emitters and detectors. Such devices are potentially enabling in healthcare applications in new diagnostic or treatment tools.

In order to maximize potential impact from this work, a comprehensive impact programme is proposed, focusing primarily on building industry contact, demonstrating the technology and exploring collaborative opportunities to develop IP and technology for UK industry. Academic impact will be ensured by publishing work at various stages in high profile and open access publications. The PDRA employed through this program and PhD students working on related areas will be involved in industry outreach efforts to add value. Potential application areas in healthcare will be identified as part of the comprehensive industry collaboration impact activities including identifying potential industrial contacts and engagement through industry outreach events.

Publications

10 25 50
 
Description New mechanisms of controlling micro-scale transfer printing processes that will enable new types of semiconductor devices to be manufactured. These processes are currently being developed and improved, currently a range of printed optical microcavity devices have been demonstrated. These structures typically were previously limited to a narrow range of compatible materials but these restrictions have now been lifted with these novel techniques, allowing for much wider ranging applications. As the project progresses further technology demonstrators will be constructed to explore potential impact on manufacturing.

Transfer printed microcavities exhibiting extremely narrow linewidth emission towards lasing have been demonstrated. This has significant potential to allow for cheaper and easier processing of microscale light emitting devices. This has also led to the first demonstration of transfer printed resonant cavity LEDs, representing a new manufacturing approach solving problems that exist with current fabrication approaches.

New fabrication processes to increase the range of materials available for transfer printing have been developed, increasing the utility of transfer printing for heterogeneous integration of wide ranging semiconductor materials and devices. This has potential as an enabling manufacturing technology in flexible electronics (wearables), medical devices, 2D materials devices and more.

New processes for transferring LEDs from their growth substrates to new substrates enabling flexible optoelectronic devices. This technique has the potential to allow low cost, manufacturing scale development of new LED based products, ranging from next generation displays to wearable electronics.

New manufacturing compatible processes for constructing photonic devices with applications in light emitters, sensors and potentially more. These processes are being developed and optimized through a follow-on commercialization funded project to allow manufacture of a range of photonic devices taking advantage of new combinations of materials enabled by these processes.

Transfer print metrology processes developed to monitor transfer print processes in situ, such as dynamic force measurements during these high speed processes.
Exploitation Route Commercialization follow-on projects for outcomes of this project are currently in progress. New technologies being developed and applied to novel optoelectronic devices. The newly developed process of transfer printing hybrid microcavities provides a platform to allow for integration of unrestricted materials into optical microcavities, not just limited to traditional semiconductor materials but spanning a wide range of material possibilities including biological materials. This technique has the potential of being picked up by wide ranging groups in fields from the physical to biological sciences. New partnerships with industry are actively being built to achieve knowledge exchange bringing technology into UK and international manufacturers. Follow-on activity to develop these partnerships to commercial exploitation are currently in progress.

Commercialization options for the new fabrication processes being developed are currently being explored including patent protection, when resolved an embargo is lifted, the results will be published in academic journals.

Metrology techniques and system developed are currently being employed to study transfer printing processes to support novel material development to enhance transfer printing parameter space with academic partners in the UK - results are expected to be published in 2024.
Sectors Electronics

Manufacturing

including Industrial Biotechology

 
Description Key new technologies to develop heterogeneous integration approaches of photonic components are the focus of an ongoing Knowledge Exchange grant working to explore the potential for these technologies to have an impact on an industrial partner. IP protection is being put in place to protect novel technology developed related to microLED applications and allow for economic impacts of this technology to be realized in collaboration with an industrial partner. Current disclosure limitations restrict publication but results will be published when disclosure restrictions allow.
First Year Of Impact 2023
Sector Digital/Communication/Information Technologies (including Software),Electronics,Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description Ino-Flex: Enabling ultra-large area ultra-parallel roll-to-roll transfer printing of high performance flexible inorganic semiconductor devices
Amount £252,918 (GBP)
Funding ID EP/V051792/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2021 
End 03/2023