Studijní program:NanotechnologieStudijní obor: Nanomateriály

(organizuje prof. J. Šedlbauer, FPP TU v Liberci)

Preparation of semiconductor nanomaterials

2014/2015

(prof. E. Hulicius, FZÚ AV ČR, v.v.i.,)

TUL PPN 2013/2014, letní semestr (čtyřhodinové přednášky)

26. 2. 2015 – 1. přednáška.

5. 3. 2014 – 2. přednáška.

19. 3. 2014 – 3. přednáška.

26. 3. 2014 – 4. přednáška.

9.4. 2014 – 5. přednáška.

16. 4. 2014 – 6. přednáška.

21. 5. 2014 – předtermín.

28. 5. 2014 – (zkouška spolu s prezentacemi)

Dále dle dohody.

Syllabus of the Technology of nanostructure preparation, nano-heterostructures – preparation, properties, applications

Eduard Hulicius, Fyzikální ústav AV ČR, v. v. i. (hulicius@fzu.cz)

1. IntroductionWhat does it means „nano“. Are current definitions correct?Definitions and introductions to nano- you can easily find in the web (Wikipedia, e.t.c.), you have semester lecture on this subject, but here is my own limited „semiconductor“(I ignore silicon) point of view and some philosophical considerations. ((No examination.)) 2. Preparation of bulk semiconductor monocrystalsExplanation of fundaments of growths methods. Parameters, properties and reasons of limits crystallographic perfectness of these crystals. Nor this is examined , but of this subject is important for understanding of epitaxy.

3. Epitaxial techniques in general(Not only semiconductor nanostructure preparation)It is crystallic growth on (usually) monocrystallic wafer (substrate) . It is possible to prepare high-quality hetero- a nano-structures of different materials. Principles, modes and types of growth. Types of epitaxy – Solid state and Liquid phase epitaxy, variants. Epitaxial growth from material point of view. SPE, LPE.This is the fundamental chapter, understanding of epitaxial growth will be examined!4. Molecular Beam Epitaxy (MBE)Explanation of basic principles of technology. MBE technology parameters, properties and reasons of its limits.5. Metalorganic Vapour Phase Epitaxy (MOVPE)Explanation of basic principles of technology. MBE technology parameters, properties and reasons of its limits. These two chapters are also fundamental. Description and scheme of MBE or MOVPE will be in each set of questions.

6. In-situ (during growth) characterisation and diagnostic.. Parameters, properties and limits of different methods.7. Ex-situ characterisation and diagnostic layers and structures.Explanation of basic principles of measuring methods. Examples of some results.You have whole semester lecture on this subject, I will stress on „in-situ“ (during the growth) – I will ask you about the most important (RHEED, RAS, …) measurements. There will be discussed from the general ex-situ measurements, only some of our examples. 8. Supporting techniques:a) Electron beam lithography; b) Evaporation and sputtering.Explanation of basic principles of these methods. Parameters of the FZU machine.Interesting, modern, expensive and for devices very important machines, but not principal for this lecture.

9. Semiconductor (nano)hetero-structures.Semiconductor heterostructures, exploitation of quantum-size properties of nanostructures, reasons of implementation, materials.Understanding of specifics of quantum-size structures will be important for students pretending for better classification.

10. Semiconductor (nano)hetero-devices.Specifics of quantum-size device properties will be subject of questions.

11. Semiconductor lasers (LD).Lesson about fluent and step parameter LDs (and LEDs) improving due to introduction of nanostructures (Quantum Wells and Dots – QW, QD).Inside of the LD and LED structures there are used very interesting nanostructures nowadays . Their more detail description can help students to understand principles of other devices.

12. Light emitting diodes (LED).The same as about LDs. -----------------------------------------------if will be time enough13. Quantum cascade lasers versus lasers with „W“ type structure.Duel of these two types of structure on real application as a source of midinfrared radiation, which can bring many applications in medicine, ecology, communications and army. Example of still not fully decided fight of top applied research in which lecturer takes active part.

In general: NANO is not only because it is small!

Quantum effect starts to be fundamental.

Well known Moor law (about exponential decreasing of size of electronic devices and subsequent increasing of memory and speed), its history and potential future scenarios.

Context with NANO.Quantum effects.

Procedures: „Bottom-up“ a „Top-down“ and also „something between“

Examples of preparation or creations of the nanostructures

„Top-down“ – „cutting“

„Bottom-up“ – „building“

„something between“– self made „self-assembled“

Nanostructure preparation can be very simple ...

or very complicated, difficult and expensive:(Electron Beam Lithography (EBL))

Paradigma of the quantum dots

Moving from atomic electron levels over electron (hole) energy band structures to again discrete electron (hole) energy levels.

Fundamental role of NANO.Quantum effects.

Atom - Solid state bulk – Quantum dot

Some of examples of nano-applicationsa) Nanorobots.b) Elektroluminescent displays based on Q-LED

(= LEDs with Quantum Dots (QD)).c) Size of QD determine colour.d) Electron Beam Lithography (EBL) can create nanosize structures.e) One of the possible timetables of nanostructure developement.f, g) Possible nanoproduct evolution.h) Nanostructure applications.i) Future R&D Directions of EU NMP Programme for the Period 2010-2015.

a)

b) Elektroluminiscenční displeje QLED vytvořené pomocí kvantových teček mají oproti dosavadním displejům hodně výhod.

Kvantové tečky jsou ostře lokalizované krystalické oblasti polovodiče o nanometrových rozměrech. Kvantové tečky jsou schopny vázat jednotlivé elektrony a pracovat s nimi, případně jsou schopny produkovat fotony,které lze použít v dalším kroku. Elektroluminiscence označuje jev, při kterém lze v určitém materiálu řídit vyzařování světla pomocí elektrického proudu nebo elektrického pole.

Tenké displeje s přesným a kontrastním vykreslováním tvarůa barev dobývají svět. Vývoj se nezastaví u dnešních displejů typu LCD nebo LED, popř. U displejůna bázi organických polymerů, tzv. OLED. Několik firem teďpřichází s pokročilou technologiíelektroluminiscence, která je založena na tzv. kvantových tečkách. Jedná se o displeje QLED.

c) Čtyři rozdílné barvy odpovídají čtyřem druhům kvantových teček. Foto: Padova University Raffaella Signorini

d)

e)

f)

g)

Nano iPod

Chocolate Chewing Gum

Cosmetics

CNT BatTextile / Clothing

GlassPhoto / Self Cleaning

Automotive Applications Tennis RacquetHead Nano Titanium

Catalysts

Anti Odor / Anti BacterialInsoles for Shoes

Air Purification / NanoBreeze

Detection of Cancerous Cells

MacBook Air

Odorless socks

Nano iPod

Chocolate Chewing Gum

Cosmetics

CNT BatTextile / Clothing

GlassPhoto / Self Cleaning

Automotive ApplicationsAutomotive Applications Tennis RacquetHead Nano Titanium

Catalysts

Anti Odor / Anti BacterialInsoles for Shoes

Air Purification / NanoBreeze

Detection of Cancerous Cells

MacBook Air

Odorless socks

Aplikace Nanostrukturh)

i) Future R&D Directions of NMP Programme for the Period 2010-2015

3. Materials Science and Engineering3.1 Present State-of-the-art3.2 Cross-cutting Research Directions in Materials

3.2.1 Materials by Design: Synthesis, Characterization, Processing & Modelling3.2.2 Understanding Surfaces and Interfacial Phenomena3.2.3 Design and Manufacturing of Multifuctional Materials 3.2.4 Design and Manufacturing of Structural Materials3.2.5 Integration of Multiple-Scale Phenomena (Molecular, Nano and Micro) in Materials Design and

Production3.2.6 Development of Computational Tools for Predicting Functional and Structural Properties of

Materials3.2.7 Metrology, Instrumentation: New Analytical Tools for Measurement of Materials Functional and

Structural Properties3.3 Materials Applications for Selective Industrial Sectors

3.3.1 Materials for Information Technologies3.3.2 Biomaterials, Biomimetcs and Biomedical Engineering3.3.3 Materials for Energy Applications3.3.4 Surface Engineering and Coatings3.3.5 Catalysis and Chemicals Technologies3.3.6 Polymers, Composites and Hybrid Materials3.3.7 Renewable Materials, Ecomaterials3.3.8 Disassembly Recovery and Recycle of Materials

3.4 Recommendations and Priority Research Directions

i) Future R&D Directions of NMP Programme for the Period 2010-2015

4. Industrial Production Systems4.1 Present State-of-the-art4.2 Cross-Cutting Research Directions in Manufacturing

4.2.1 New Business Models4.2.2 Adaptive Manufacturing4.2.3 Networking in Manufacturing4.2.4 Digital Knowledge-based Engineering4.2.5 Emerging Technologies4.2.6 ICT for Manufacturing

4.3 Exploitation of the Convergence of Technologies4.3.1 Next-generation HVA Products4.3.2 Education and training in “Learning Factories”4.3.3 Disruptive Factory: “Bio-nano” convergence4.3.4 Disruptive Factory: “Bio-cogno-ICT” convergence

4.4 Cross-cutting Research Directions in Production Systems4.4.1 Batch and Continuous Production Systems4.4.2 Scale-up, Scale-down Developments and Process Intensification4.4.3 Enabling Technologies (e.g., On-line Monitoring, On-line Sensors, Process Optimization and

Control, Supply Chain Management)4.4.4 Digital Production (integration of product design and production systems)4.4.5 New Products/Services and New Production Paradigms4.4.6 Alternative, Renewable and Novel Feedstocks and Processes for Chemicals and Materials

Production4.5 Recommendations and Priority Research Directions

1) Preparation and properties of the bulk crystalsGrowth from melted material at melting point.2) Explanation of importance and principles and comparison with other monocrystal preparation methodsWhy so monstrous, expensive, danger and demanding technology equipments

The name epitaxy origins from Greek epi-taxis which means „arranged on" was introduced by L. Royer at 1936.It is monocrystalic growth on (usually) monocrystalic substrate (wafer). Growth is not (usually) epitaxial when lattice constant difference is bigger than 15%.

Epitaxial growth – advantages, new possibilities, limits. Homo- and hetero- epitaxy.Equation of minimum of energy.Principle of the epitaxial growth.Atoms or molecules of the compound, which we would like to deposit on suitable substrate, are transported to its surface, which have to be atomically clean – cleaned from oxides and sorbants - and atomically smooth (only with atomic steps due to disorientation of the monocrystalic substrate). On the surface the atoms will be physisorbed, and after that chemisorbed to the crystal structure. By this way atomic layers and all structure are grown.http://www.fzu.cz/~movpe/index_en.html

Semiconductor technologies

Preparation and properties of the bulk crystals:

<— Bridgeman or Horizontal Gradient Freeze (HGF)

Vertical „decreasing“ cooling:

Czochralsky method

<—

Monocrystal growth by Czochralsky technology

Semiconductor (mono)crystals

and other:

https://www.youtube.com/watch?v=AMgQ1-HdElM

https://www.youtube.com/watch?v=4Q_n4vdyZzc

Bulk monocrystals, have impresive parametres -(atomic periodicity of monocrystal lattice more than one meter!), but they are not crystalographicly perfect nad for majority of electronic, namely optoelectronic, applications are not suitable. The reason is high temperature during their creation from melted material. We have to prepare materials and structures using epitaxial technologies, which work at lower temperatures.

Semiconductor (mono)crystals – conference Berlin 2011

Monocrystal growth by horizontal Bridgman technology

Monocrystal growth by horizontal Bridgman technology

Monocrystal growth by horizontal Bridgman technology

Monocrystal growth by horizontal Bridgman technology

Bulk monocrystals, have impressive parameters -(atomic periodicity of monocrystal lattice more than one meter!), but they are not crystalographically perfect and for majority of electronic, namely optoelectronic, applications are not suitable. The reason is high temperature during their creation from melted material. We have to prepare materials and structures using epitaxial technologies, which work at lower temperatures.

End of the first part

Next:

Epitaxial growth of nanostructures