Optical characterization of InGaAsN, GaAs quantum wells [Elektronische Ressource] : effects of annealing and determination of the band offsets / vorgelegt von Massimo Galluppi

Galluppi

Sujets

• Physik

Informations

• Publié par: philipps-universitat_marburg
• Publié le: 01 janvier 2006
• Nombre de lectures: 14
• Langue: English
• Poids de l'ouvrage: 12 Mo

Extrait

Optical characterization of InGaAsN / GaAs quantum wells:
Effects of annealing and determination of the band offsets


DISSERTATION
zur
Erlangung des Doktorgrades
der Naturwissenschaften
(Dr. rer. nat.)

dem Fachbereich Physik
der Philipps-Universität Marburg
vorgelegt von
Massimo Galluppi
aus Rom (Italien)



Marburg / Lahn 2005








Vom Fachbereich Physik der Philipps-Universität Marburg
als Dissertation angenommen am 09.12.2005

Erstgutachter: Dr. habil. Wolfgang Stolz
Zweitgutachter: Prof. Dr. Sergei Baranovski

Tag der mündlichen Prüfung am 15.12.2005



Table of contents
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Table of contents

Figures......................................................................................................................................................4

Introduction.............11

Chapter 1.................15
Characteristics of Dilute Nitrides.........................................................................................................15
1.1 Fundamental band structure properties and theories on dilute nitrides.............................................16
1.1.1 Giant bowing of the band gap energy ........................................................................................16
1.1.2 Theoretical models.....................................................................................................................18
1.1.2.1 The band anti-crossing model ............................................................................................19
1.1.2.2 Pseudopotential theory of dilute nitrides.............................................................................21
1.1.3 Conduction band states .............................................................................................................22
1.1.4 Conduction band dispersion: electron effective mass................................................................24
1.1.5 Band alignment ..........................................................................................................................25
1.2 Structural properties ..........................................................................................................................27
1.2.1 Annealing effects on the structure of dilute nitrides ...................................................................30
1.3 On the radiative and non-radiative recombination processes in dilute nitrides .................................32
1.3.1 Low energy tail of the photoluminescence spectrum .................................................................34
1.3.2 Temperature dependence of the PL peak energy and PL linewidth ..........................................36
1.3.3 Power dependence of the PL peak emission.............................................................................38
1.3.4 PL decay time ............................................................................................................................40
1.3.5. Annealing effects.......................................................................................................................41
1.3 Conclusions of the first chapter .........................................................................................................45

1 Table of contents
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Chapter 2................................................................................................................................................48
Experimental Techniques .....................................................................................................................48
2.1 Growth...............................................................................................................................................48
2.1.1 MBE at Infineon: sample structure .............................................................................................49
2.2 Annealing...........................................................................................................................................52
2.3 Sample characterization ....................................................................................................................54
2.3.1 Photoluminescence spectroscopy..............................................................................................54
2.3.2 Surface photo voltage spectroscopy ..........................................................................................55
2.3.3 Other characterization techniques .............................................................................................58

Chapter 3................................................................................................................................................60
Effects of Growth Parameters and Annealing Conditions on the Optical Properties of Dilute
Nitrides................60
3.1 Influence of the growth temperature on the optical and morphological properties of InGaAsN ........61
3.2 Influence of the indium content on InGaAsN quantum wells .............................................................65
3.3 Influence of annealing .......................................................................................................................68
3.3.1 Annealing effects on the indium series ......................................................................................69
3.3.2 Annealing effects on the optical and morphological properties of InGaAsN quantum wells grown
at different temperatures.................................................................................................................70
3.3.3 Influence of the annealing atmosphere on the optical and morphological properties of dilute
nitrides ............................................................................................................................................73
3.3.4 Correlation between optical and morphological properties of dilute nitrides ..............................78
3.3.4.1 Time resolved PL measurements .......................................................................................78
3.3.4.2 Modification of the carrier localization degree after annealing............................................80
3.3.4.2 Defects in dilute nitrides......................................................................................................86
3.4 Conclusions of the third chapter ........................................................................................................91

Chapter 4................................................................................................................................................95
Band Offsets Analysis in Dilute Nitrides.............................................................................................95
4.1 Application of surface photovoltage spectroscopy to determine the band offsets of quantum well
structures ............................................................................................................................................96
4.1.1 Optical transitions detected by surface photovoltage measurements........................................97
4.1.1.1 The first and the last step in the spectra.............................................................................99
2 Table of contents
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4.1.1.2 The third step in the spectra .............................................................................................100
4.1.1.3 The second step in the spectra.........................................................................................106
4.1.2 Refined interpretation of the surface photovoltage spectra......................................................108
4.1.3 Determination of the band offsets ............................................................................................110
4.1.4 Advantages of the method: comparison with other techniques................................................112
4.2 Application of the method to InGaAsN / GaAs structures................................................................114
4.2.1 Influence of the nitrogen content on the energetic states and band offsets of InGaAsN quantum
wells..............................................................................................................................................114
4.2.1.1. Application of the band anti-crossing model to simulate the energy levels in dilute nitrides
.................................................................................................................................................116
4.2.1.2. Evolution of the conduction and valence practical band offsets with varying nitrogen
content......................................................................................................................................118
4.2.2 Influence of the indium content on the energetic states and band offsets of InGaAsN quantum
wells......................................................................................................................................