AMORPHOUS CHALCOGENIDE-BASED OPTOELECTRONIC PLATFORM FOR NEXT-GENERATION OPTOELECTRONIC TECHNOLOGIES

Lead Research Organisation: University of Southampton
Department Name: Optoelectronics Research Centre

Abstract

Materials discovery, development and modification has been a key factor in developing the world we live in. The study of materials which exhibit electrical or optical properties has played a major role in enabling all of modern technology and in particular electronics, computing and communications. As these technologies have been developed existing materials have also been modified and pushed close to their limits of what is technical feasible. An example of this is the advances made in silicon (Si) based microelectronics which has led to speed, which relates to power of processing, becoming critical, with a reduction in the size of the microelectronics used to achieve this. This approach is ultimately limited as sizes reduce; thus alternative methods must be sought. Optical communication and data transfer is widely known as being much quicker as information can be moved at the speed of light. However, whenever it interacts with electronics, such as when broadband optical fibre is connected to a computer the data transfer and processing must slow down to the speed of the microelectronic processors. There is a strong desire and compelling argument therefore to develop an 'optoelectronic' technology which is a hybrid of the optical and electronic systems but without the current limitations imposed by the two current technologies working independently. This proposal will seek to apply one of the most developed materials modification tools that is fundamental to modern microelectronics, ion-implantation, to a class of materials that show unique potential for enabling future optoelectronic technologies. These materials, known as chalcogenides, are already widely used in applications such as photovoltaics (solar cells), memory (e.g. DVDs), and advanced optical devices (e.g. lasers). Currently however they are used solely as either electronic materials or optical materials, with different types of chalcogenides used for each. Their properties that allow use in these separate application types gives them the potential to be developed so that the excellent optical properties of one material can be combined with the excellent electronic properties of another and vice versa. One of the reasons that this has yet to be done is that it has proved to be extremely difficult to modify their electronic properties during the material preparation which typically involves melting at high temperatures. Anything that is added to the materials, referred to as doping, is ineffective under these conditions due to the ability of the material to reorder itself whilst melted to cancel out the desired effect. In this programme of work, we will modify the properties by introducing dopants into the chalcogenide materials below their melt temperature, thus not allowing the material to reorder. This will be undertaken using ion-implantation which allows precise control of the type of impurity introduced. As a result of this work, we will develop for the first time an understanding of how these unique materials can be modified in a controlled way. We will then use this to develop better models of the origin of the materials' electronic and optical properties which will allow us to develop optimised materials. We will also develop prototype devices that will lead the way to the development of a truly optoelectronic technology. This programme will establish the UK as leaders in this field and therefore directly contribute to the continuing growth of the knowledge economy. We will train the next generation of scientists and engineers in state-of-the-art techniques to ensure that the UK maintains the expertise base required for this, aim to ensure the impact of this work is maximised and accelerated where possible, and communicate the results widely including to all stakeholders in this research.
 
Description We have developed a process in which chalcogenide glass can be modified by doping and/or ion implantation to give it similar properties to the semiconductor silicon. We have also shown that these modified glasses can be made into electronic devices which enable for example, switching of electrical signals.
Exploitation Route This is the first step to creating electronic and optical devices from these materials.
Sectors Digital/Communication/Information Technologies (including Software),Electronics,Energy

URL https://www.research.manchester.ac.uk/portal/richard.curry.html
 
Description Research Publications including Nature Communications UK Patent Application Follow on funding through an EPSRC responsive mode proposal now awarded and due to start 1 April 2016. Project details: EP/N020278/1 Development and Application of Non-Equilibrium Doping in Amorphous Chalcogenides
First Year Of Impact 2013
Sector Electronics
Impact Types Economic

 
Description Development and Application of Non-Equilibrium Doping in Amorphous Chalcogenides
Amount £261,632 (GBP)
Funding ID EP/N020278/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2016 
End 03/2019
 
Description Wearable and flexible technologies enabled by advanced thin-film manufacture and metrology
Amount £2,476,881 (GBP)
Funding ID EP/M015173/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2015 
End 04/2019
 
Description Applied Materials 
Organisation Applied Materials
Country United States 
Sector Private 
PI Contribution Advising UK representative of Applied Materials, Dr Jonathan England, on the research advanced made on chalcogenide devices.
Collaborator Contribution Enhanced understanding of the commerical requirement for semiconductor processing equipment related to this project.
Impact Preparation of materials used to present results of this project to high level management at Applied Instruments Head Office.
Start Year 2011
 
Description Smart Materials for Data Storage 
Organisation Ilika
Department Ilika Technologies Ltd.
Country United Kingdom 
Sector Private 
PI Contribution HAMR is a technology designed to enable the next big increase in the amount of data that can be stored on a hard drive. It uses a new kind of media magnetic technology on each disk that allows data bits, or grains, to become smaller and more densely packed than ever, while remaining magnetically stable. A small laser diode attached to each recording head heats a tiny spot on the disk, which enables the recording head to flip the magnetic polarity of each very stable bit, enabling data to be written. Our research team provided expertise in our knowledge of advanced materials to the industrial partner Seagate to help them indentify materials more suitable in the hard drives they were developing.
Collaborator Contribution The Nanomaterials for Data Storage project has successfully demonstrated new materials with new capabilities to improve read write transducer reliability and performance in next generation hard drive products. High thermal conductivity materials have been processed at Seagate's wafer fabrication facility with follow on electrical testing to verify that the nitride based materials have enabled reduced thermal effects in the transducer, translating into a 25% gain in the ability to set the distance between the head and the disk. This will enable reduced time to product launch for the Heat Assisted Magnetic Recording (HAMR) hard drive technology due to reach the market in early 2019. Advanced material synthesis and test capability at the partner organisations, Ilika and University of Southampton was used to facilitate material optimisation and exploration with many alternative options. The Nanomaterials for Data Storage has resulted in strong working relationship between Seagate, llika and the University of Southampton. As a result of this another Innovate UK funded project, Photonic Material Process for Data Storage, is underway. The aim of this project is to put in place a mechanism for continued business interaction between Seagate and Ilika. Also, the University of Southampton has been able to quickly demonstrate material properties and measurements in several areas that are of interest to Seagate. It is hoped that one of these areas can become the focus on a future Innovate UK funded project. The partners are actively working on this at the moment.
Impact Ellipsometry of 2D materials Improved annealing processes for 2D materials Processes for lower temperature deposition of 2D materials Invited to Participate Knowledge Transfer Network, UK led workshop: Contact: Monika Dunkel monika.dunkel@ktn-uk.org Participated in Flexible and Printed Electronics, Displays & Photonics demonstrator workshop, 21 November 2017, Cambridge
Start Year 2016
 
Title Ion implantation in amorphous chalcogenides 
Description Technical Field The present invention relates to ion implantation in amorphous chalcogenides. More particularly, but not exclusively, the present invention relates to ion implantation in an amorphous chalcogenide material in a thermoelectric device. Background of the Invention Thermoelectric devices employ the thermoelectric effect to convert a temperature difference into an electric current, or to create a thermal gradient through the application of an electric current. Examples of thermoelectric devices include thermoelectric generators, thermocouples and thermopiles, which use the Seebeck effect to generate electricity, and Peltier heat pumps, which use the Peltier effect to pump heat from a cold side of the heat pump to a hot side. It is generally desirable to increase the efficiency of thermoelectric devices, so that a larger current can be generated for a given thermal gradient, and more heating/cooling power can be provided by a given power supply. 
IP Reference GB1410098.6 
Protection Patent application published
Year Protection Granted 2014
Licensed Commercial In Confidence
Impact Discussions with a UK Venture Capital company on possible route to exploitation
 
Title Amorphous Chalcogenide Rectifying Device 
Description An aluminium implanted GeSe electronic device shows rectifying behaviour when electrically characterized for its current-voltage characteristics. As expected a breakdown effect is also seen at negative bias. Results are repeatable.Thermopower and Hall Effect measurements indicate that an n-type chalcogenide may have been achieved through the implantation of Al. GeSe is intrinscially p-type. Al implantation took place at 35 KeV with a dosage of 3 x 10^15 ions. SIMS Time of Flight analysis by two independent contractors confirmed penetration of the Al to a depth of approximately 60 nm. Measurements on a control device, in which no implantation was performed, showed no rectification providing further evidence that the implanted Al formed a pn junction. 
Type Of Technology Physical Model/Kit 
Year Produced 2015 
Impact Further funding through Development and Application of Non-Equilibrium Doping in Amorphous Chalcogenides 
 
Title Confirmation of Carrier Reversal in Amorphous Chalcogenide 
Description To further understand and investigate the ion implanted chalcogenide materials as a novel phase change application, thermopower measurements have been taken on thin films with various ion dosages, including bismuth (Bi) implanted GeTe, Bi implanted GeSe, Bi implanted SbTe and molybdenum (Mo) implanted SbTe films. During the experiments, we observed for the first time carrier reversal, ie. p-n carrier type switching, when the dose of the implanted ions increased above 1^16 Bi ions/cm3 . With this measurement, we have demonstrated further the potential for an amorphous chalcogenide to provide semiconductor and rectifying properties in the form of a p-n junction device. 
Type Of Technology New Material/Compound 
Year Produced 2015 
Impact Patent filed Ion implantation in amorphous chalcogenides Inventor: Hewak Daniel William (GB) (+2) Application WO2015185940A1 Daniel Hewak University of Surrey Priority 2014-06-06 • Filing 2015-06-05 • Publication 2015-12-10 
 
Title Flexible Thermoelectric Device 
Description A functioning thermoelectric device which converts waste heat directly to electrical power has been demonstrated using chalcogenide glasses developed in collaboration with the University of Surrey and Cambridge. We are currently optimizing performance. 
Type Of Technology Physical Model/Kit 
Year Produced 2015 
Impact Ion implantation in amorphous chalcogenides Inventor: Hewak Daniel William (GB) (+2) Application WO2015185940A1 Daniel Hewak University of Surrey Priority 2014-06-06 • Filing 2015-06-05 • Publication 2015-12-10 
 
Description An amorphous ion implanted chalcogenide optoelectronic information processing platform 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation paper presentation
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The doping of crystalline semiconductors, in particular Si, has proven to be the key technological step that underpins the majority of today's electronic technologies. Of all the effects observed, the ability to control the electronic properties of these materials, providing n-type, p-type conducting and insulating regions via ion-implantation, has revolutionised manufacturing and enabled Moore's law to continue to be held. Ion-implantation continues to provide new opportunities for technological advances in microelectronics, for example, such methods can also be used to stabilize or activate specific interactions within the materials within localized regions.



We report first on ion implantation of a broad range of elements into chalcogenide thin films spanning sulphides, selenides and tellurides. The properties of these films are investigated pre and post implantation. Second, targeting the most promising dopants and chalcogenide compounds, we describe design, fabrication and characterisation of a series of ion implanted amorphous PN junctions in the Ge:Se family of glasses, using both metallic (Al) and gaseous implanted ions (O). The junctions produced show good rectification while at higher electric field exhibiting memory switching behaviour. This suggests the possiblitie of unique devices exhibit, rectification along with a controlled asymmetric polarity dependant behaviour, which shows great promise in realising next generation synaptic devices.



We believe that through the ion implantation process, in selected chalcogenide materials, a low cost production line method of producing integrated diode/memory cells with next generation cognitive information processing capability can be realised for use in future cross bar array architectures.
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Results published in Nature Communications
Year(s) Of Engagement Activity 2013
 
Description Materials Research Exchange, 12 March 2018, London 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact The 2018 Materials Research Exchange and Investor Showcase, organised by the Knowledge Transfer Network and Innovate UK and supported by EPSRC and Dstl provides an excellent platform to help develop commercial success of UK-generated materials research and innovation.

Taking place on 12 and 13 March, 2018 at the Business Design Centre, London it will provide an ideal opportunity to absorb current trends and take a glimpse of future innovations. The UK is an acknowledged global hub of excellence in materials research and know-how. This event will demonstrate the groundbreaking new materials and processes to industry to accelerate the process of taking these through to commercialisation.

From metals, powders and textiles to graphene and polymers - innovations in advanced materials research have numerous applications across a wide range of sectors. MRE2018 will be the largest and finest materials innovation event of the year... designed by those working in materials for the materials sector to engage with key application sectors in the UK and beyond.
Year(s) Of Engagement Activity 2018
URL http://www.rsc.org/events/detail/30124/materials-research-exchange-and-investor-showcase-2018