N A T I O N A L P E R S P E C T I V E S

43Public Service Review: Science & Technology: issue 8

The colour of light is determined by its wavelength or

frequency, indicating how fast the associated

electric field of the light wave changes direction.

However, a large fraction of the electromagnetic spectrum

is invisible to the human eye. This is also true for terahertz

(THz) radiation corresponding to frequencies around

1012 (trillion) Hertz. Terahertz radiation has low energy

and is thus biologically non-hazardous, penetrates

conventionally opaque materials like textiles or organic

tissue, and has a high chemical sensitivity due to

molecule-specific absorption. Thus terahertz science and

technology is a promising contemporary field of physics,

with great prospects for progress in diverse scientific

areas and a wide application potential in material

characterisation, medicine, chemistry, environment

monitoring, security, biomedical imaging, and chemical/

biological sensors.

However, this frequency range, lying between microwave

and optical frequencies, is only scarcely used – a

consequence of the lack of commercially available solid

state sources. Current research involves the search for and

design of new sources and detectors of THz radiation as

well as the use of THz light in various applications and

basic research. The latter in particular is on the agenda of

the Regensburg Terahertz Center (TerZ), though

considerable effort is also assigned to pushing the

technology forward.

‘…terahertz science andtechnology is a promisingcontemporary field of physics,with great prospects forprogress in diverse scientificareas and a wide applicationpotential…’

The laboratories of the Terahertz Center at Regensburg

allow experiments at frequencies covering the near

infrared (1014 Hz) to microwave radiation (1010 Hz)

including the whole terahertz regime. Several laser and

spectroscopic systems permit studies from low to ultra

high radiation intensities. The objects of scientific interest

are low-dimensional electron or hole systems, which can

also be found in various transistor structures or in

graphene, a novel and promising material for future

electronics. Terahertz radiation allows for the exploration

of the spin degree of freedom of the charge carriers, ie. the

miniscule quantised magnetic moment that is attached to

electrons. The spin together with the elementary charge

constitutes the field of spintronics, which aims to use the

spin of the charge carriers in electronics to achieve new

functionalities.

TerZ is also part of the Regensburg Collaborative Research

Center (SFB 689) funded by the German Research

Foundation (DFG). An important goal of TerZ is fostering

networks between various local groups and colleagues from

all over the world interested in the experimental facilities of

the centre. The cooperating laboratories have by now

accumulated a vast amount of know-how based on the rich

palette of available terahertz equipment. Most notable is an

institutionalised cooperation between the Ioffe Institute

and the St. Petersburg State Polytechnic University, as well

as the Lomonosov Moscow State University, which is

funded by the International Bureau of Germany’s Federal

Ministry of Education and Research (BMBF). The resulting

establishment of the German-Russian Terahertz Centre is

an important step in joining forces between Europe and

Russia in the field of terahertz research.

TerZ Director Professor Sergey Ganichev and Professor Dieter Weiss, of the University of

Regensburg, shed light on developments in the growing field of terahertz research…

Illuminating terahertz science

Professor Sergey GanichevDirector of TerZ Tel. +49 (0)941 943 2050Sergey.Ganichev@physik.uni-regensburg.dewww.physik.uni-regensburg.de/forschung/ganichev

Professor Dieter Weiss Tel. +49 (0)941 943 3197Dieter.Weiss@physik.uni-regensburg.dewww.physik.uni-regensburg.de/forschung/weissUniversity of Regensburg

ST8 S Ganichev ATL 43.qxd:1 17/9/10 10:16 Page 1

E lectronics are all around us.PCs, PDAs, laptops, videomobile phones, digital

cameras, or MP3 players are just afew examples that have become apart of our daily lives. Electronicsdepends largely on semiconductordevices like transistors that work byswitching flows of electrons on andoff. Many recent technological andconceptual breakthroughs have madeelectronic devices smaller, smarterand more powerful. The discovery ofthe giant magnetoresistance (GMR),which has provided increased sensitivity for measuring minisculemagnetic fields, has enabled furthershrinkage of hard drives, thusfostering new applications. In theseGMR devices, not only the charge ofelectrons but also their spin is used.The spin is the electron’s magneticmoment and is responsible for ferro-magnetic properties of matter. Thesimultaneous use of charge and spinin electronics has opened a newscientific field, called spintronics.Many believe that the integration ofthe spin in electronics has the poten-tial for reduced power consumption,higher speed or added functionalitysuch as non-volatile memory. Besidesthe spin, monoatomic sheets ofcarbon, called graphene (see Fig. 1),have recently entered the stage andmight revolutionise electronics. Thishope rests largely on the much higherelectron velocities in this new mate-rial. Graphene has been heralded asan important discovery with thepotential to revolutionise electronicsin the same way that silicon did.

Both fields – semiconductor spin-tronics and graphene electronics/spintronics – are still in their infancyand constitute the hottest area inbasic semiconductor research. In all of these research areas, the

condensed matter section of thephysics department of the University of Regensburg is involved. Accordingto the funding ranking 2009 of theGerman Science Foundation (DeutscheForschungsgemeinschaft, DFG),condensed matter physics at Universityof Regensburg belongs to the threetop players in Germany. Below we givea short profile of the institution anddescribe some of its activities.

The Collaborative Research CentreSFB 689 on ‘Spin Phenomena inReduced Dimensions’ focuses onsemiconductor-, molecular- andgraphene-spintronics. The centre,funded by the DFG, is coordinated byexperimental physicist Dieter Weissand addresses the storage, transportand manipulation of spins for novelelectronic devices and concepts.Ferromagnetic semiconductors,graphene and carbon nanotubes aswell as magnetic molecules andmaterials with strong spin-orbit inter-action form a broad material basis forthe realisation of new spin-effectsand their application for novel func-tionalities. In particular, magneticsemiconductors are interestinghybrids as they are both ferromag-netic and semiconducting. This cansimply be achieved by incorporatingmanganese atoms into the conven-tional optoelectronic material gallium

arsenide (GaAs): ferromagnetic(Ga,Mn)As results. The main problemwith this material, currently limitingdevice perspectives, is that the Curie-temperature at which ferromag-netism sets in is still well below-70°C. At present we are checkinghow coupling of the well-known ferromagnet iron and (Ga,Mn)Asmight open prospects for deviceoperations at ambient temperatureconditions. The newest addition inthe family of ferromagnetic nanos-tructures are (Ga, Mn)As nanowires(see Fig. 2), which are grown by acombination of self-organisation andconventional molecular beam epitaxy.Other hybrid systems like molecules,carbon nanotubes or graphene with ferromagnetic contacts, explored inRegensburg and other places, expandthe spintronics concept to molecularand carbon-based systems.Molecules as electronic devicesrepresent the ultimate level of theminiaturisation of electronic/spin-tronic circuits. The formation ofelectric contacts, the control of theelectronic and optical properties ofsingle molecules, as well as theprocessing and storage of informationat the molecular level represent novelchallenges for nanoscience.

Electronics is based on the flow ofelectrons (electric current). As theelectrons carry a magnetic momentthat has, due to the rules of quantummechanics, only two possible values,called spin-up and spin-down, onecan also envision a situation in whicha spin current but no charge currentflows. This is indeed experimentallypossible and the physical properties –as well as the application potential ofthis new type of current – are beingintensively investigated. Spin currentscan also be excited by means of

International cooperationnurtures scholarship andrevolutionary research…

Spin, graphene, THz andelectronics

profile

44 Public Service Review: Science & Technology: issue 8

Fig. 1: Electron micrograph of a graphene filmsuspended between two metallic contacts(courtesy of B Söll and J Eroms, University

of Regensburg)

ST8 Terahertz PRO 44.qxd:Layout 1 16/9/10 16:02 Page 1

terahertz (THz) radiation. The physicsand application of THz radiation is inthe focus of the Regensburg TerahertzCentre (TerZ), directed by SergeyGanichev. THz radiation with frequen-cies between the microwave regimeand visible light has low energy andis thus biologically non-hazardous,penetrates conventionally opaquematerials like textiles or organictissue and has a high chemical sensi-tivity due to molecule specificabsorption. This invisible light is notonly a powerful tool to study spin-orbit interaction for spintronicsresearch but also has wide applicationpotential in material characterisation,medicine, chemistry, environmentmonitoring, security, biomedicalimaging, and chemical/biologicalsensors. At present we are investi-

gating, amongst others, photocurrentsin graphene using THz radiation.

All the described activities take placein a university environment. The role ofuniversities in society is on one handto ‘produce’ knowledge, ie. doingresearch, and on the other hand toeducate young people. As Humboldt’sidea of unity of research and educa-tion is dwarfed by the reality ofundergraduate education in Germany,it is partly still alive in graduateprogrammes. Only graduate studentsworking on topics at the forefront ofcurrent research can convey newdevelopments into society. InRegensburg we offer what is so far theonly coordinated PhD programme oncarbon-based electronics in Germanyinvolving many projects on graphene.The DFG-funded Research TrainingGroup GRK 1570 is coordinated byMilena Grifoni. In GRK 1570 weexplore electric, magnetic and alsomechanical properties of graphene,nanopatterned graphene and carbonnanotubes, consisting of ‘rolled up’graphene. Before carbon-based elec-tronics could take over from silicon,many fundamental physical challengesneed to be addressed. One is theabsence of an energy gap in graphenemonolayers, which prevents switchingon and off electric currents easily.

Basic research, as conducted here,rests to a large extent on interna-tional cooperation. Hence all threeinstitutions – SFB 689, GRK 1570and TerZ – focus on internationalteamwork. Apart from many individualcontacts, an institutionalised cooper-ation between the Ioffe Institute andthe Polytechnic University, both in StPetersburg, as well as the LomonosovUniversity in Moscow, are mostnotable. Cooperation is funded by theInternational Bureau of Germany’sFederal Ministry of Education andResearch (BMBF). The resultingestablishment of the German-RussianTerahertz Centre is an important stepin joining forces between Europe andRussia in the field of semiconductorresearch. Quite recently the DFG also established, together with theJapanese funding agency JST, a jointGerman-Japanese Research Unit(Fogru 1483) on new electronicconcepts in which the universities inWürzburg, Regensburg, Tokyo andSendai closely work together,involving also the authors of thisarticle as principal investigators.

Professor Sergey Ganichev

Tel: +49 (0)941 943 2050Fax: +49 (0)941 943 1657

Sergey.Ganichev@physik.uni-regensburg.dewww.physik.uni-regensburg.de/forschung/ganichev

Professor Dieter Weiss

Tel: +49 (0)941 943 3197Fax: +49 (0)941 943 3196

Dieter.Weiss@physik.uni-regensburg.dewww.physik.uni-regensburg.de/forschung/weiss

Physics DepartmentUniversity of Regensburg

www.physik.uni-regensburg.de

profile

45Public Service Review: Science & Technology: issue 8

Fig. 2: Electron micrograph of (Ga,Mn)As nanowires (courtesy of E Reiger, A Rudolph and CButschkow, University of Regensburg)

Fig. 3: Dieter Weiss (left), Coordinator of thecollaborative research centre SFB 689 and

Sergey Ganichev (right), Director of TerZ

ST8 Terahertz PRO 44.qxd:Layout 1 16/9/10 16:02 Page 2

science& technology 08

Daniel KammenRealising and achieving aclean energy future

Core values Peeling back the layers of Italianapplied research

Danilo TürkImagining new outcomes forEuropean science

Janez PotocnikDeveloping a logical frameworkfor a green economy

Frank De WinneLife aboard the InternationalSpace Station

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Germany is experiencing something of a boom

period in scientific research and innovation.

Increased investment in science across all sectors

is reaping rewards for Berlin and the Germany economy.

Talking to Public Service Review, Dr Georg Schütte,

State Secretary at the Federal Ministry of Education and

Research, explains the thinking behind the German

approach to science both now and in the future.

What advances have occurred in German science andtechnology in recent years?In recent years, Germany has stepped up its efforts to

interlink education, research and innovation. There has

been an increasing awareness in the past 20 years that

economic policy is not just industrial policy, but that it

requires a combination of industrial policy, science policy,

and research and innovation policy. To that end, the

German government has devoted increased financial

resources to research and innovation.

This is reflected in the figures – in 2005, the federal

government spent €9bn on research and development. In

the 2010 budget, €12.7bn is earmarked for this area. R&D

investments from the German private sector increased

from €38.7bn in 2005 to more than €46bn in 2008. As for

the number of people who work in R&D, the numbers

went up by almost 30,000 between 2005 and 2008. In total,

there were more than 330,000 researchers, laboratory

technicians and engineers employed in R&D in Germany

in 2008. There has not just been a policy change, but also

a positive change in the general climate. We have created

a culture of innovation, which is particularly important

during a time of economic and financial crisis.

How important does the German government view sciencefunding at a time of global economic difficulty?The German government made a very clear decision that

funding for research and innovation should not be

neglected in the current economic crisis. On the contrary,

the federal government committed itself to spending

an additional €12bn on education and research in the

current legislative period until 2013. That is a very strong

commitment given the fact that the German government

also aims to reduce the budget deficit, which was

increased tremendously in order to avert the immediate

danger of an economic recession. So we are tackling two

challenges at the same time – budget consolidation and

further investment in education and research.

This means other branches of the German government

also have to support research and innovation.

How is Germany approaching the subject of futuretechnologies such as microelectronics, robotics and nanotechnology?The strategic framework we have developed for the

innovation policy of the federal government is known as

the ‘High Tech Strategy’. Its aim is to tackle large global

challenges, such as climate and energy, health and

nutrition, mobility, security and communication. We are

implementing this through a mission-oriented approach

in which we design and develop forward-looking projects

with very hands-on objectives. One example is electric

mobility – we plan to have one million electric vehicles

on German streets by 2020. In order to make that

possible, key technologies play a crucial role, including

biotechnology, nanotechnology, robotics and optical

technology. The federal government and the ministry I

represent provide what we call ‘project funding’, for both

German universities and consortia of German companies

and German universities. We offer direct funding to

further develop these technologies as a basis for technical

innovation and economic success.

What are the goals of the German government in terms ofits future technology programme?We plan to extend the High Tech Strategy, which is more

than just a strategic framework, because it will translate

into concrete actions. We will work on building clusters

Dr Georg Schütte, of the Federal Ministry of Education and Research, reveals to

Public Service Review why Germany remains dedicated to heavy investment in R&D…

High Tech strides

N A T I O N A L P E R S P E C T I V E S

32 Public Service Review: Science & Technology: issue 8

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that bring together, both regionally and thematically, the

key players from research and industry to further develop

new technologies. Discussions concerning tax credits for

research and development are ongoing. It is important to

nurture a climate of innovation.

Germany is also striving to improve the financial

conditions for innovation, by providing easier access to

venture capital. ‘Validation initiatives’ are another means

of enhancing innovation, focusing on the innovation

potential of new research discoveries to try to evaluate

whether research results are suitable for direct application.

Of course, we are continuing to support and strengthen all

aspects of the German education and research system –

improving conditions at German universities, increasing

the number of students entering German universities, and

internationalising the science and research system in

general. To this end, the federal government has

developed an internationalisation strategy. The main

objective of the Bologna Process was to harmonise the

higher education sector in Europe, and there is still a long

way to go in this process. We are convinced that further

harmonisation and collaboration in European higher

education will, in the long run, contribute to increasing

the competitiveness of Europe as a whole. This is

definitely necessary at a time when we face demographic

changes in Europe as well as increased international

competition, not only in science and research, but also in

various economic fields.

Finally, Germany is in direct contact with the European

Commission, the European Council and our partner

countries in Europe in order to contribute to the

‘Innovation Union’. The High Tech Strategy has led to

the development of a number of interesting ideas and

models that could be applied at a European level as well.

We Europeans have to improve conditions and meet the

challenges ahead, and we can only achieve this if we close

ranks within Europe.

N A T I O N A L P E R S P E C T I V E S

Dr Georg Schütte State SecretaryFederal Ministry of Education and Research, Germany Tel: +49 (0) 228 99 57 3034www.bmbf.de

33Public Service Review: Science & Technology: issue 8

Internationalising German research: Dr Annette SchavanDr Annette Schavan, Federal Minister of Education and Research, is charged with developing Germany’s science,

research and innovation expertise. Since her appointment in 2005, she has overseen a marked increase in funding for

Germany’s scientific research and is now moving towards the next phase of increased internationalisation and

collaboration among German scientists and elsewhere in the global scientific community.

Commenting on the Federal Report on Research and Innovation 2010 in June of this year, Minister Schavan highlighted

the successes of the country’s scientific policy over the last five years as well as emphasising her determination to keep

the German scientific community at the very forefront of international science.

“The number of publications and patents in Germany has increased in recent years by 20%, so we are seeing a clear,

positive trend,” the minister declared. “Abroad, there is great interest in research in Germany. There is also a high

interest in research collaborations with our universities. The structural development of the science system is a priority

for us. We will forge new alliances between academia and industry. We not only invest but also implement new

concepts. This strengthens our international position.

“All this has such weight, because the proportion of goods, products, services and procedures based on research

represents 45% of the value of the German economy,” Schavan continued. “We are not world champions of low wages,

but we want to be world champions of innovation. That depends on the economic power of tomorrow.”

Expanding on the issue of Germany’s influence in global science and research circles, Dr Schavan highlighted countries

such as China, India and Brazil whose economies are developing on the back of increased investment in science and

innovation. The minister emphasised that another recent trend within these countries, in particular, was a desire to

collaborate with other nations around the world.

“The report also indicates that we need to deal with trends outside of Germany,” Dr Schavan

observed. “It was therefore right that we have agreed, in the coalition agreement, to put in the

internationalisation of our research policy a focus on developmental and emerging markets. In the

coming years, we will do all we can to cooperate with excellent partners. 90% of knowledge is

generated outside Germany. This means that internationalisation remains in this legislative

period, a key project.”

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