Scientists / Open questions

Herbert Kroemer

Semiconductor physics; heterostructure devices

2000 Nobel Prize in Physics

44 questions

Microscopic origin of the large forward-bias nonideality ( $n\approx1.8$ ) of InAs/AlSb n-N isotype heterojunctions grown on GaAs
Quantitative determination and experimental validation of cathode control characteristics for the Gunn effect under imperfect contacts
Effective ionic charges and the interstitial electrostatic potential in zinc-blende-type semiconductors: reconciling charge measures and bounding the accuracy of bulk band-energy references
First-principles prediction of semiconductor heterojunction band offsets and interface charge at the kT accuracy needed for device design (Kroemer's 1983 lineup problem)
Solvent-composition-dependent phase separation of a thermotropic main-chain liquid-crystal copolyester in 3,5-bis(trifluoromethyl)phenol/ $n$ -butanol mixtures: mechanism and nature of the precipitating phase
Population-inversion-induced band-structure instability in long-period one-dimensional superlattices: survival beyond the idealized static model and experimental observability
Open issues in establishing the (110) orientation as the preferred orientation for molecular beam epitaxial growth of zincblende-on-diamond heterostructures (GaAs on Ge, GaP on Si)
Self-contained elementary justification of the crossed-field derivation of the Thomas $1/2$ factor in spin–orbit coupling
Atomic-scale nucleation mechanism and nucleation-dependent electronic quality of the GaAs-on-Si(001) polar-on-nonpolar interface
Microscopic origin of the reduced transition energies of few-monolayer InAs/AlSb quantum wells
A quantitative multiple-Andreev-reflection theory of the anomalous quasiparticle transport in Nb-contacted InAs-AlSb quantum wells: the giant precursor of induced superconductivity and sub-flux-quantum-periodic resistance oscillations
Disorder-limited quantized conductance in long InAs/AlSb split-gate ballistic constrictions: surface-donor fluctuation statistics, the subband-spacing criterion, and charge-trapping effects
Extending Kroemer's two-sided bound on the Bose–Fermi partition-function difference beyond the spinless, noninteracting, continuum classical regime
Quantitative theory and experimental verification of quasi-direct transitions in ultra-narrow GaSb-AlSb (100) quantum wells, and their realization in other indirect-gap well systems
Determination of the delta-function interface potential strength Γ in the effective-mass description of abrupt semiconductor heterojunctions, and its relation to atomic-scale interface structure
Open validation of the $\Gamma$ – $L$ carrier partition, strain- and nonparabolicity-inclusive subband modeling, and temperature dependence of normal-incidence far-infrared intersubband absorption in heavily $n$ -doped nonalloy GaSb–AlSb superlattices
Mechanistic understanding of CH4/H2 reactive ion etching of InAs, InP, GaAs, and GaSb: etch-product identification and rate-limiting steps
Strong-field anomalous transport and burst-like $70\pm 10$ MHz current oscillations in ordered tetrathiafulvalene iodide (TTF-I $_n$ , $n\cong 0.7$ ): mechanism of the proposed electrically driven iodine-sublattice order-disorder transition
Gallium-beam reduction of silicon oxide on silicon: quantitative kinetics, process window, and the role of deliberate preoxidation
Donor-profile-free inversion of C–V profiles through isotype n–n heterojunctions: extracting interface charge and band offsets with quantified Debye-length and probe-geometry validity bounds

Back to open problems

Microscopic origin of the large forward-bias nonideality (n≈1.8n\approx1.8n≈1.8) of InAs/AlSb n-N isotype heterojunctions grown on GaAs

Quantitative determination and experimental validation of cathode control characteristics for the Gunn effect under imperfect contacts

Effective ionic charges and the interstitial electrostatic potential in zinc-blende-type semiconductors: reconciling charge measures and bounding the accuracy of bulk band-energy references

First-principles prediction of semiconductor heterojunction band offsets and interface charge at the kT accuracy needed for device design (Kroemer's 1983 lineup problem)

Solvent-composition-dependent phase separation of a thermotropic main-chain liquid-crystal copolyester in 3,5-bis(trifluoromethyl)phenol/nnn-butanol mixtures: mechanism and nature of the precipitating phase

Population-inversion-induced band-structure instability in long-period one-dimensional superlattices: survival beyond the idealized static model and experimental observability

Open issues in establishing the (110) orientation as the preferred orientation for molecular beam epitaxial growth of zincblende-on-diamond heterostructures (GaAs on Ge, GaP on Si)

Self-contained elementary justification of the crossed-field derivation of the Thomas 1/21/21/2 factor in spin–orbit coupling

Atomic-scale nucleation mechanism and nucleation-dependent electronic quality of the GaAs-on-Si(001) polar-on-nonpolar interface

Microscopic origin of the reduced transition energies of few-monolayer InAs/AlSb quantum wells

A quantitative multiple-Andreev-reflection theory of the anomalous quasiparticle transport in Nb-contacted InAs-AlSb quantum wells: the giant precursor of induced superconductivity and sub-flux-quantum-periodic resistance oscillations

Disorder-limited quantized conductance in long InAs/AlSb split-gate ballistic constrictions: surface-donor fluctuation statistics, the subband-spacing criterion, and charge-trapping effects

Extending Kroemer's two-sided bound on the Bose–Fermi partition-function difference beyond the spinless, noninteracting, continuum classical regime

Quantitative theory and experimental verification of quasi-direct transitions in ultra-narrow GaSb-AlSb (100) quantum wells, and their realization in other indirect-gap well systems

Determination of the delta-function interface potential strength Γ in the effective-mass description of abrupt semiconductor heterojunctions, and its relation to atomic-scale interface structure

Open validation of the Γ\GammaΓ–LLL carrier partition, strain- and nonparabolicity-inclusive subband modeling, and temperature dependence of normal-incidence far-infrared intersubband absorption in heavily nnn-doped nonalloy GaSb–AlSb superlattices

Mechanistic understanding of CH4/H2 reactive ion etching of InAs, InP, GaAs, and GaSb: etch-product identification and rate-limiting steps

Strong-field anomalous transport and burst-like 70±1070\pm 1070±10 MHz current oscillations in ordered tetrathiafulvalene iodide (TTF-In_nn​, n≅0.7n\cong 0.7n≅0.7): mechanism of the proposed electrically driven iodine-sublattice order-disorder transition

Gallium-beam reduction of silicon oxide on silicon: quantitative kinetics, process window, and the role of deliberate preoxidation

Donor-profile-free inversion of C–V profiles through isotype n–n heterojunctions: extracting interface charge and band offsets with quantified Debye-length and probe-geometry validity bounds

Microscopic origin of the large forward-bias nonideality ( $n\approx1.8$ ) of InAs/AlSb n-N isotype heterojunctions grown on GaAs

Solvent-composition-dependent phase separation of a thermotropic main-chain liquid-crystal copolyester in 3,5-bis(trifluoromethyl)phenol/ $n$ -butanol mixtures: mechanism and nature of the precipitating phase

Self-contained elementary justification of the crossed-field derivation of the Thomas $1/2$ factor in spin–orbit coupling

Open validation of the $\Gamma$ – $L$ carrier partition, strain- and nonparabolicity-inclusive subband modeling, and temperature dependence of normal-incidence far-infrared intersubband absorption in heavily $n$ -doped nonalloy GaSb–AlSb superlattices

Strong-field anomalous transport and burst-like $70\pm 10$ MHz current oscillations in ordered tetrathiafulvalene iodide (TTF-I $_n$ , $n\cong 0.7$ ): mechanism of the proposed electrically driven iodine-sublattice order-disorder transition