Spontaneous Ordering in Semiconductor Alloys

The phenomenonofspontaneous ordering in semiconductoralloys, which can be categorized as a self-organized process, is observed to occur sponta- neously during epitaxial growth of certain ternary alloy semiconductors and results in a modification of their structural, electronic, and optical properties. There has been a great dealofinterest in learning how to control this phenome- non so that it may be used for tailoring desirable electronic and optical properties. There has been even greater interest in exploiting the phenomenon for its unique ability in providing an experimental environment of controlled alloy statistical fluctuations. As such, itimpacts areasofsemiconductorscience and technology related to the materials science ofepitaxial growth, statistical mechanics, and electronic structure of alloys and electronic and photonic devices. During the past two decades, significant progress has been made toward understanding the mechanisms that drive this phenomenon and the changes in physical properties that result from it. A variety of experimental techniques have been used to probe the phenomenon and several attempts made atproviding theoretical models both for the ordering mechanisms as well as electronic structure changes. The various chapters of this book provide a detailed account of these efforts during the past decade. The first chapter provides an elaborate account of the phenomenon, with an excellent perspective of the structural and elec- tronic modifications itinduces.

Table of Contents:
1. Basic Aspects of Atomic Ordering in III-V Semiconductor Alloys.- 1. Introduction.- 2. CuPt-B Atomic Ordering.- 3. TP-A and CuPt-A Atomic Ordering.- 4. Ordering Mechanisms.- 5. Concluding Remarks.- References.- 2. The Nature and Origin of Atomic Ordering in Group III-V Antimonide Semiconductor Alloys.- 1. Introduction.- 2. Atomic Ordering in Group III-V Antimonide Semiconductors Alloys.- 3. Origins of Atomic Ordering in Semiconductor Alloys.- 4. Conclusions.- References.- 3. Effects of the Surface on CuPt Ordering During OMVPE Growth.- 1. Introduction.- 2. Review of the Ordering Processes.- 3. Effects of Surfaces.- 4. Effects of Surfactants.- 5. Tellurium.- 6. Antimony.- 7. Summary.- References.- 4. X-Ray Diffraction Analysis of Ordering in Epitaxial III-V Alloys.- 1. Introduction.- 2. Overview of X-Ray Diffraction Theory.- 3. Long-Range Order.- 4. Reciprocal Space Mapping of Ordered Domains.- 5. Short-Range Order.- 6. Lateral Compositional Modulation.- 7. Summary.- References.- 5. Surface Morphology and Formation of Antiphase Boundaries in Ordered (GaIn)P—A TEM Study.- 1. Introduction.- 2. Transmission Electron Microscopy.- 3. Experimental.- 4. Results and Discussion.- 5. Summary.- References.- 6. X-Ray Characterization of CuPt Ordered III-V Ternary Alloys.- 1. Introduction.- 2. Results from TED and TEM Studies.- 3. X-Ray Diffraction Measurements.- 4. Structural Model and Diffraction Theory.- 5. Effect of the Atomic Displacements.- 6. Examples of Data Analyses.- 7. Determination of the Order Parameter.- 8. Summary.- References.- 7. Diffraction and Imaging of Ordered Semiconductors.- 1. Introduction.- 2. Ordered Semiconductors.- 3. Dynamical Diffraction.- 4. Analysis.- 5. Conclusions.- References.- 8. X-Ray Analysis of the Short-Range Order in the Ordered-AlloyDomains of Epitaxial (Ga,In)P Layers by DAFS of Superlattice Reflections.- 1. Introduction.- 2. Discussion.- 3. Conclusions.- References.- 9. Ballistic Electron Emission Microscopy and Spectroscopy Study of Ordering-Induced Band Structure Effects in Ga0.52In0.48P.- 1. Introduction.- 2. BEEM Technique.- 3. Experimental Set-Up.- 4. Results and Analysis.- 5. Conclusions.- References.- 10. Cross-Sectional Scanning Tunneling Microscopy as a Probe of Local Order in Semiconductor Alloys.- Reference.- 11. The Physics of Tunable Disorder in Semiconductor Alloys.- 1. Introduction.- 2. Ordering Induced Band Gap Reduction and Valence Band Splitting.- 3. Ordering Induced Optical Anisotropy or Polarization.- 4. Ordering Induced Changes in Effective Mass.- 5. Reflectance Difference Spectroscopy Study of Ordered Structure.- 6. Statistical Aspects of Spontaneous Ordering.- 7. Band Offset Between Ordered GaInP and GaAs.- 8. Novel Superlattices—Orientational Superlattices.- 9. Extrinsic Effects in Ordered GaInP.- 10. Conclusions.- References.- 12. Spectroscopic Study of the Interface and Band Alignment at the GaInP(Partially Ordered)/GaAs Heterojunction under High Pressure and High Magnetic Field.- 1. Introduction.- 2. Background.- 3. Sample Preparation and Characterization.- 4. Experimental Details.- 5. Experimental Results.- 6. Discussion.- 7. Conclusions.- References.- 13. Polarization Effects in the (Electro)absorption of Ordered GaInP and Their Device Applications.- 1. Introduction.- 2. Ordering Induced Effects on the Optical Transitions in GaInP.- 3. Polarization dependent Electro-Absorption.- 4. Polarization-Sensitive Devices.- 5. Conclusions and Outlook.- References.- 14. Phonons in Ordered Semiconductor Alloys.- 1. Introduction.- 2. Raman Scattering Studies.- 3. InfraredStudies.- 4. Phonons in Double Variant Ordered GaInP2.- 5. Conclusions.- References.- 15. Effects of Ordering on Physical Properties of Semiconductor Alloys.- 1. Introduction.- 2. Dependence on the Degree of LRO.- 3. Energy Level Shift and Splitting.- 4. X-Ray Structure Factor.- 5. Electric Field Gradient.- 6. Coupling of Ordering with Strain.- 7. Optical Anistropy in Ordered Alloys.- 8. Spin Polarization in Ordered Alloys.- 9. Effects of Stacking Faults.- 10. Summary.- References.- 16. Polarization Charges at Spontaneously Ordered (In,Ga)P/GaAs Interfaces.- 1. Background.- 2. Carrier Distribution at Interfaces.- 3. Effect of Spontaneous Ordering.- 4. Band Offsets and Interfacial Charges.- 5. Order-Induced Polarization Charges.- 6. Conclusions.- References.- Author Index.