Pub Date : 2020-12-15DOI: 10.1201/9781003072829-13
D. Miller
{"title":"Optics for digital information processing","authors":"D. Miller","doi":"10.1201/9781003072829-13","DOIUrl":"https://doi.org/10.1201/9781003072829-13","url":null,"abstract":"","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79278563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1093/oso/9780198759867.003.0017
S. Tiwari
This chapter extends this book’s discussion of bandstructure, band discontinuities and transport—much of the text up to this point—to a manipulation of them through stress and strain. Semiconductors can be strained through a variety of techniques, with strained growth leading to a strained layer, and pattern definition leading to local strained region, being the most common. Strain changes bandstructures and interface bandedge energies, distorts and warps bands, removes degeneracies, affects scattering and thus changes a variety of properties. Following a continuum description of stress-strain relationships, effects of stress—biaxial, hydrostatic and uniaxial—are analyzed for bandstructure and transport in electron bands, light-hole bands, heavy-hole bands and split-off bands in group IV and group III-V semiconductors. Transport effects can be particularly strong in quantum-confined conditions, where changes in density of states can be significant, along with other bandstructure and scattering changes.
{"title":"Stress and strain effects","authors":"S. Tiwari","doi":"10.1093/oso/9780198759867.003.0017","DOIUrl":"https://doi.org/10.1093/oso/9780198759867.003.0017","url":null,"abstract":"This chapter extends this book’s discussion of bandstructure, band discontinuities and transport—much of the text up to this point—to a manipulation of them through stress and strain. Semiconductors can be strained through a variety of techniques, with strained growth leading to a strained layer, and pattern definition leading to local strained region, being the most common. Strain changes bandstructures and interface bandedge energies, distorts and warps bands, removes degeneracies, affects scattering and thus changes a variety of properties. Following a continuum description of stress-strain relationships, effects of stress—biaxial, hydrostatic and uniaxial—are analyzed for bandstructure and transport in electron bands, light-hole bands, heavy-hole bands and split-off bands in group IV and group III-V semiconductors. Transport effects can be particularly strong in quantum-confined conditions, where changes in density of states can be significant, along with other bandstructure and scattering changes.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77291175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1093/oso/9780198759867.003.0019
S. Tiwari
This chapter discusses remote processes that influence electron transport and manifest themselves in a variety of properties of interest. Coulomb and phonon-based interactions have appeared in many discussions in the text. Coulomb interactions can be short range or long range, but phonons have been treated as a local effect. At the nanoscale, the remote aspects of these interactions can become significant. An off-equilibrium distribution of phonons, in the limit of low scattering, will lead to the breakdown of the local description of phonon-electron coupling. Phonons can drag electrons, and electrons can drag phonons. Soft phonons—high permittivity—can cause stronger electron-electron interactions. So, plasmon scattering can become significant. Remote phonon scattering too becomes important. These and other such changes are discussed, together with phonon drag’s consequences for the Seebeck effect, as illustrated through the coupled Boltzmann transport equation. The importance of the zT coefficient for characterizing thermoelectric capabilities is stressed.
{"title":"Remote processes","authors":"S. Tiwari","doi":"10.1093/oso/9780198759867.003.0019","DOIUrl":"https://doi.org/10.1093/oso/9780198759867.003.0019","url":null,"abstract":"This chapter discusses remote processes that influence electron transport and manifest themselves in a variety of properties of interest. Coulomb and phonon-based interactions have appeared in many discussions in the text. Coulomb interactions can be short range or long range, but phonons have been treated as a local effect. At the nanoscale, the remote aspects of these interactions can become significant. An off-equilibrium distribution of phonons, in the limit of low scattering, will lead to the breakdown of the local description of phonon-electron coupling. Phonons can drag electrons, and electrons can drag phonons. Soft phonons—high permittivity—can cause stronger electron-electron interactions. So, plasmon scattering can become significant. Remote phonon scattering too becomes important. These and other such changes are discussed, together with phonon drag’s consequences for the Seebeck effect, as illustrated through the coupled Boltzmann transport equation. The importance of the zT coefficient for characterizing thermoelectric capabilities is stressed.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77308126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1093/oso/9780198759867.003.0004
S. Tiwari
The introduction of the various computation techniques for determining bandstructures, their implications and their pitfalls is the scope of this chapter, which ends up with a realistic representation of the bandstructures of semiconductors. Approaches to the calculation of semiconductor bandstructures—tight binding, orthogonalized plane waves, density functional and k · p—are discussed, with an emphasis on the physical implications through toy models. The effective mass theorem and Wannier functions are introduced as tools to explore nonlocalized and localized behaviors. Spin’s consequence in the valence bandstructure through spin-orbit coupling and the Luttinger Hamiltonian is emphasized. Semiconductor bandgap behavior in group IV, group III-V and group II-VI compounds is explored, including those of nitrides and gapless semiconductors, together with insights into the common semiconductors’ electron bandstructures, density of states and van Hove singularities. The chapter concludes with a discussion of phonon bandstructures.
{"title":"Bandstructures","authors":"S. Tiwari","doi":"10.1093/oso/9780198759867.003.0004","DOIUrl":"https://doi.org/10.1093/oso/9780198759867.003.0004","url":null,"abstract":"The introduction of the various computation techniques for determining bandstructures, their implications and their pitfalls is the scope of this chapter, which ends up with a realistic representation of the bandstructures of semiconductors. Approaches to the calculation of semiconductor bandstructures—tight binding, orthogonalized plane waves, density functional and k · p—are discussed, with an emphasis on the physical implications through toy models. The effective mass theorem and Wannier functions are introduced as tools to explore nonlocalized and localized behaviors. Spin’s consequence in the valence bandstructure through spin-orbit coupling and the Luttinger Hamiltonian is emphasized. Semiconductor bandgap behavior in group IV, group III-V and group II-VI compounds is explored, including those of nitrides and gapless semiconductors, together with insights into the common semiconductors’ electron bandstructures, density of states and van Hove singularities. The chapter concludes with a discussion of phonon bandstructures.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82088418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1142/9789814261517_0004
S. Tiwari
This chapter discusses the electronic, phononic and atomic behavior at surfaces. Symmetry breaking at the surface causes the emergence of new properties as the state description changes. Starting with an introduction of the semi-classical view, a bulk-based view of workfunction and electron affinity and cautions related to them, toy models are employed to explore the evolution of states at the surface. For electrons, propagating Bloch states persist to the surface but there are also states that are confined. Properties of these confined states and surface states are explored. The implications of stress and of surface reconstruction are discussed to elucidate the atomic rearranging that arises in semiconductors of interest when symmetries change. The state evolution approach is then extended to probe surface phonons. Again, bulk modes persist up to the surface, but there can also be surface-confined modes as well as surface-propagating modes.
{"title":"Semiconductor surfaces","authors":"S. Tiwari","doi":"10.1142/9789814261517_0004","DOIUrl":"https://doi.org/10.1142/9789814261517_0004","url":null,"abstract":"This chapter discusses the electronic, phononic and atomic behavior at surfaces. Symmetry breaking at the surface causes the emergence of new properties as the state description changes. Starting with an introduction of the semi-classical view, a bulk-based view of workfunction and electron affinity and cautions related to them, toy models are employed to explore the evolution of states at the surface. For electrons, propagating Bloch states persist to the surface but there are also states that are confined. Properties of these confined states and surface states are explored. The implications of stress and of surface reconstruction are discussed to elucidate the atomic rearranging that arises in semiconductors of interest when symmetries change. The state evolution approach is then extended to probe surface phonons. Again, bulk modes persist up to the surface, but there can also be surface-confined modes as well as surface-propagating modes.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75251346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1093/oso/9780198759867.003.0016
Sandip Tiwari
This chapter examines noise, another example of cause and chance at work, and an example of the statistical fluctuations in the response arising from random events. Approaches to understanding randomness embedded in signals are discussed along with the notion of ergodic behavior, autocorrelation and the use of the Wiener-Khintchin theorem. Fluctuations and noise in semiconductors are analyzed by exploring charge transport between plates under scattering. The quantum and thermodynamic links at resonance are emphasized. The Nyquist relationship, a very general relationship, is derived. Partition thermal noise under limited channels is explored, and shot noise is discussed. Low frequency noise arising as random telegraph noise due to charge trapping and detrapping is analyzed. Noise in a parameter—resistance, for example—can be due to multiple interactions. An example of this is resistance fluctuation due to mobility and carrier fluctuations, which in many materials can be parameterized through the Hooge parameter.
{"title":"Noise","authors":"Sandip Tiwari","doi":"10.1093/oso/9780198759867.003.0016","DOIUrl":"https://doi.org/10.1093/oso/9780198759867.003.0016","url":null,"abstract":"This chapter examines noise, another example of cause and chance at work, and an example of the statistical fluctuations in the response arising from random events. Approaches to understanding randomness embedded in signals are discussed along with the notion of ergodic behavior, autocorrelation and the use of the Wiener-Khintchin theorem. Fluctuations and noise in semiconductors are analyzed by exploring charge transport between plates under scattering. The quantum and thermodynamic links at resonance are emphasized. The Nyquist relationship, a very general relationship, is derived. Partition thermal noise under limited channels is explored, and shot noise is discussed. Low frequency noise arising as random telegraph noise due to charge trapping and detrapping is analyzed. Noise in a parameter—resistance, for example—can be due to multiple interactions. An example of this is resistance fluctuation due to mobility and carrier fluctuations, which in many materials can be parameterized through the Hooge parameter.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87077301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-24DOI: 10.1093/oso/9780198759867.003.0015
S. Tiwari
This chapter discusses Onsager relationships. These relationships result from the linear response at the macroscale off-equilibrium from the reversibility of the microscale and represent an example of cause and chance at work. Flux-flow formalism—flux densities tied to thermodynamic forces—is developed to build the generalized linear relationships for heat, electric, chemical composition and free energy. The relationships are then applied to examples from previous chapters—thermoelectric and others—to show how results of interest can be derived more easily through exploiting Onsager relationships’ linearity and reciprocity relationships. The chapter discusses Onsager relationships with respect to Ohm’s law, Fourier’s law, Fick’s law, Darcy’s law, Gibbs free energy, thermoelectric effects and fluctuation-dissipation.
{"title":"Onsager relationships","authors":"S. Tiwari","doi":"10.1093/oso/9780198759867.003.0015","DOIUrl":"https://doi.org/10.1093/oso/9780198759867.003.0015","url":null,"abstract":"This chapter discusses Onsager relationships. These relationships result from the linear response at the macroscale off-equilibrium from the reversibility of the microscale and represent an example of cause and chance at work. Flux-flow formalism—flux densities tied to thermodynamic forces—is developed to build the generalized linear relationships for heat, electric, chemical composition and free energy. The relationships are then applied to examples from previous chapters—thermoelectric and others—to show how results of interest can be derived more easily through exploiting Onsager relationships’ linearity and reciprocity relationships. The chapter discusses Onsager relationships with respect to Ohm’s law, Fourier’s law, Fick’s law, Darcy’s law, Gibbs free energy, thermoelectric effects and fluctuation-dissipation.","PeriodicalId":44695,"journal":{"name":"Semiconductor Physics Quantum Electronics & Optoelectronics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73103569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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