Novel InSb quantum dots monolithically grown on silicon for low cost mid-infrared light emitting diodes

Lead Research Organisation: Lancaster University
Department Name: Engineering

Abstract

There is great worldwide interest in the mid-infrared spectral region (2-5 um) as it contains the fundamental absorption bands of a number of pollutant and toxic gases and liquids. These include gases such as carbon dioxide, carbon monoxide and hydrogen chloride which require accurate, in-situ multi-component monitoring in a number of industries such as oil-rigs, coal mines, land-fill sites and car exhausts. Strong absorption bands also exist for drug intermediates, pharmaceuticals, narcotics and biochemicals where the absorption strength is typically 2 orders of magnitude stronger than in the near-infrared allowing highly selective and sensitive detection in the fields of: environmental monitoring, bio-medicine, industrial process control and health and safety. There is also an atmospheric transmission window between 3.6 and 3.8 um which enables free space optical communication and thermal imaging in both civil and military situations as well as the development of infrared countermeasures for homeland security. However, these applications have yet to be fully exploited due to the lack of efficient and affordable light sources and detectors. This work proposes the growth and fabrication of a new light emitting diode (LED) architecture based on indium antimonide (InSb) quantum dots onto low cost silicon (Si) substrates. This will revolutionize how we utilize these devices and lead to a dramatic scaling in the cost and size of the optical systems to enable their widespread uptake. It will also enable the photonic components to be directly embedded into electronic circuits which would open up a new field of mid-infrared photonic integrated circuits. This would generate entirely new technology in areas such as integrated 'lab-on-a-chip' sensors and compact biochips bringing great commercial benefits and opportunities to the UK.

In the last few years, there has been significant progress in the development of mid-infrared devices using interband cascade lasers and type II superlattices. However these structures are extremely complex and expensive to fabricate and are grown on gallium antimonide (GaSb) substrates which are of poor quality, high cost (~50 times the cost of Si) and are only available in small sizes. Growth onto silicon would be most desireable to enable cost effective manufacture and to ensure future commercial success. The major obstacle in direct epitaxial growth of III-Vs onto Si is the large lattice mismatch between the III-V/Si interface, resulting in a large density of threading dislocations (TDs) which strongly deteriorate the device performance. This project shall overcome this by implementation of a new device design based on InSb quantum dots on low defect density GaSb buffer layers grown on Si. The key advantages are the mechanical robustness and very low sensitivity of the quantum dots to TD compared to bulk or quantum well structures, and the suppression of non-radiative Auger recombination to increase the quantum efficiency. In a quantum well device, every threading dislocation which propagates through it will act as a non-radiative centre drastically reducing the device performance. However in a QD, each TD will only 'kill' one or a few isolated dots which will not significantly affect device performance providing the TD density in the buffer layer can be reduced to moderate-to-low levels. Low defect density GaSb buffer layers shall be realized through novel 'interfacial misfit arrays (IMF)' and dislocation filtering layers designed to bend and annihilate TD generated at the III-V/Si interface.

The Si based mid-infrared LEDs will be developed in close collaboration with academic (University of Southampton and University of Montpellier) and industrial (Compound Semiconductor Technologies and Gas Sensing Solutions) project partners to evaluate device performance for use in practical applications which will help to achieve future commercialisation.

Planned Impact

The development of new materials and technologies highlighted in this research has the potential to impact over a very wide range of communities both economically and socially. The main fields are;

1. Environmental monitoring: There is great interest in environmental monitoring of pollutant and toxic gases such as carbon dioxide, carbon monoxide and methane which have strong absorption lines in the mid-infrared region. This would address a wide range of industries including; power stations, oil-rigs, landfill sites, natural gas, waste treatment, agricultural industries and pharmaceutical processing. However the uptake of the current technology is limited by cost, size and complexity. The silicon based LEDs developed in this work will provide a route towards low cost and high volume manufacturing of high performance gas sensors. This will enable widespread and enhanced gas monitoring capabilities and will lead to improved air quality in urban and industrial areas.

2. Security and Defence: progress towards the development of sources for the 3.6-3.8 um atmospheric transmission window will enable secure free space optical communications in both civil and military applications as well as the development of infrared countermeasures for homeland security and to help combat terrorist threats. In the longer term, higher performance focal plane arrays for use in next generation thermal imaging equipment used for surveillance and explosive detection can be envisaged. Monolithic integration with Si readout integrated circuits (ROICs) will enable higher pixel count, lower cost and higher device reliability.

3. Healthcare: There are significant opportunities for exploitation in healthcare due to the specific sensitivity of various biomolecular components in the mid-infrared spectral range. These include; bio-medical analysis where mid-infrared wavelengths allow rapid analysis of proteins in the body to identify cancerous cells and infrared detection of drugs and bio agents using breath analysis. In the longer term, integration onto Si will enable these processes and measurements to be performed on a single chip enabling handheld and personalized healthcare devices.

Collaboration with relevant industrial and academic partners as highlighted in the pathways to impact document will help to achieve impact in these highlighted fields.
 
Description We have achieved an international leading position and UK capability in the epitaxial growth of high quality GaSb epilayers on Silicon with low defect density. Subsequently, this has enabled us to produce low-cost novel mid-infrared light emitting diodes and detectors on Silicon for applications in environmental gas monitoring, security and defence, industrial process control and health and safety. This will lead to a decrease in the manufacturing costs which will enable their widespread uptake. The research also opens up the possibility for the photonic components to be directly embedded into electronic circuits which could open up new fields in mid-infrared photonic integrated circuits for applications in 'lab-on-a-chip' sensors. The results have been published in ACS Photonics which has attracted widespread attention from the semiconductor media (please see http://www.semiconductor-today.com/news_items/2019/feb/lancasteruni_190219.shtml). This research as already attracted further investment from Huawei where the aim is to commercialise 1.55 µm GaSb based telecom lasers onto Silicon for high volume manufacturing and integration with photonic integrated circuits. Throughout this project, we have also developed close collaborations with the University of Montpellier (France) and Nelson Mandela Metropolitan University (South Africa) who have provided access to world-class characterisation facilities.
Exploitation Route We have established a UK capability to produce high quality GaSb epitaxial material and mid-infrared LEDs/detectors onto low cost Silicon substrates. This technology could be used by several UK industries to access new markets in gas sensing, security and defence and renewable energy. Huawei has already invested from outputs arising from this research where the aim is to commercialise 1.55 µm GaSb based telecom lasers onto Silicon for high volume manufacturing and integration with photonic integrated circuits. We are also currently in the process of discussing our results with Gas Sensing Solutions (GSS) to develop and implement the LEDs for environmental gas monitoring through a funded project such as Innovate UK or a Knowledge Transfer partnership. The new capabilities could also be integrated into a future UK academic facility.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Energy,Environment,Manufacturing, including Industrial Biotechology,Security and Diplomacy

URL http://www.semiconductor-today.com/news_items/2019/feb/lancasteruni_190219.shtml
 
Description Within this research project we have established a UK capability at Lancaster to grow high quality GaSb epilayers on low cost Silicon substrates by Molecular Beam Epitaxy (MBE). This has attracted investment from Huawei where the aim is to commercialise 1.55 µm GaSb based lasers onto Silicon for high volume manufacturing and integration with photonic integrated circuits.
First Year Of Impact 2016
Sector Digital/Communication/Information Technologies (including Software)
Impact Types Economic

 
Description EPSRC Impact Acceleration Account
Amount £10,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2017 
End 12/2017
 
Description Faculty of Science and Technology's Research Impact Fund
Amount £5,000 (GBP)
Organisation Lancaster University 
Sector Academic/University
Country United Kingdom
Start 01/2019 
End 07/2019
 
Description Huawei
Amount £146,000 (GBP)
Organisation Huawei Technologies 
Sector Private
Country China
Start 11/2016 
End 03/2020
 
Title MBE method for GaSb/Si 
Description Established a UK capability at Lancaster to grow high quality GaSb epilayers on low cost Silicon substrates by Molecular Beam Epitaxy (MBE). 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? No  
Impact This cability has attracted investment from Huawei where the aim is to commercialise 1.55 µm GaSb based lasers onto Silicon for high volume manufacturing and integration with photonic integrated circuits. 
 
Description University of Montpellier 
Organisation University of Montpellier
Country France 
Sector Academic/University 
PI Contribution Myself and members of my research team have visited the NanoMIR group at the University of Montpellier to characterise and grow epitaxial material for the project.
Collaborator Contribution The University of Montpellier have provided access to world-class facilities and provided advice/consultancy to the project.
Impact Development of new strain balanced InAlAs/GaAs mid-infrared material. Characterisation of GaSb/Si epilayers.
Start Year 2017
 
Description University of Warwick 
Organisation University of Warwick
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Provided GaSb/Si samples grown by Molecular Beam Epitaxy (MBE) for Transmission Electron Microscopy (TEM)
Collaborator Contribution Provided TEM characterisation of samples and interpretation.
Impact Joint Publication in ACS Photonics: Mid-Infrared InAs/InAsSb Superlattice nBn Photodetector Monolithically Integrated onto Silicon. / Delli, Evangelia; Letka, Veronica; Hodgson, Peter David; Repiso Menendez, Eva; Hayton, Jonathan; Craig, Adam Patrick; Lu, Qi; Beanland, R; Krier, Anthony; Marshall, Andrew Robert Julian; Carrington, Peter James. In: ACS Photonics, 16.01.2019.
Start Year 2017
 
Description Visit to NMMU, South Africa 
Organisation Nelson Mandela Metropolitan University
Country South Africa 
Sector Academic/University 
PI Contribution Provided GaSb/Si epitaxial material grown at Lancaster for further optical studies. Provided InGaSb/GaAs QD samples for optical studies
Collaborator Contribution Characterised GaSb/Si material and provided access to novel optical characterisation equipment.
Impact Detailed Photoluminescence (PL) studies of GaSb/Si material which is currently been prepared for publication. PL and modelling performed on InGaSb/GaAs QDs which has been published in Semiconductor Science and Technology: Optical and structural properties of InGaSb/GaAs quantum dots grown by molecular beam epitaxy. / Hodgson, Peter David; Bentley, Matthew; Delli, Evangelia; Beanland, R; Wagener, Magnus C. ; Botha, Johannes Reinhardt ; Carrington, Peter James. In: Semiconductor Science and Technology, Vol. 33, No. 12, 125021, 14.11.2018.
Start Year 2017
 
Description British Science Week 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact We presented our research to the department (including staff, undergraduates and postgraduates) as part of the British Science Week (10-19th March). The purpose was to publicise our work to the faculty and engage in networking and discussion.
Year(s) Of Engagement Activity 2017
 
Description University Community Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact We highlighted our research through demonstrations, hand-outs and discussions to the general public at the Lancaster University Community Day. The purpose was to publicise and explain our research to the general public.
Year(s) Of Engagement Activity 2017