Nick Holonyak

Bio: Nick Holonyak is an academic researcher from University of Illinois at Urbana–Champaign. The author has contributed to research in topics: Quantum well & Laser. The author has an hindex of 52, co-authored 549 publications receiving 13608 citations. Previous affiliations of Nick Holonyak include Urbana University.

Disorder of an AlAs‐GaAs superlattice by impurity diffusion

Abstract: Data are presented showing that Zn diffusion into an AlAs‐GaAs superlattice (41 Lz∼45‐A GaAs layers, 40 LB∼150‐A AlAs layers), or into AlxGa1−xAs‐GaAs quantum‐well heterostructures, increases the Al‐Ga interdiffusion at the heterointerfaces and creates, even at low temperature (<600 °C), uniform compositionally disordered AlxGa1−xAs. For the case of the superlattice, the diffusion‐induced disordering causes a change from direct‐gap AlAs‐GaAs (Eg∼1.61 eV) to indirect‐gap AlxGa1−xAs (x∼0.77, EgX∼2.08 eV).

Impact ionisation in multilayered heterojunction structures

Abstract: Calculations are reported showing that in multilayered heterojunction structures the effective impact ionisation rates for electrons and holes can be very different, even if they are the same in the basic bulk materials. The reason for this is the difference in the band-edge discontinuities for electrons and holes and the lower phonon mean free path for holes in quantum well structures.

Stripe‐geometry quantum well heterostructure AlxGa1−xAs‐GaAs lasers defined by defect diffusion

Abstract: Impurity‐free selective layer disordering, utilizing Si3N4 masking stripes and SiO2 defect (vacancy) sources, is used to realize room‐temperature continuous AlxGa1−xAs‐GaAs quantum well heterostructure lasers.

Laser operation of a heterojunction bipolar light-emitting transistor

Abstract: Data are presented demonstrating the laser operation (quasicontinuous, ∼200K) of an InGaP–GaAs–InGaAs heterojunction bipolar light-emitting transistor with AlGaAs confining layers and an InGaAs recombination quantum well incorporated in the p-type base region Besides the usual spectral narrowing and mode development occurring at laser threshold, the transistor current gain β=ΔIc∕ΔIb in common emitter operation decreases sharply at laser threshold (65→25,β>1)

Disorder of an AlAs‐GaAs superlattice by silicon implantation

Abstract: Data are presented on a 126‐layer AlAs‐GaAs superlattice which has been selectively disordered by silicon implantation. Silicon ions, implanted at 375 keV and a dose of 1014 cm−2, yield a compositionally disordered region 0.33 μm thick centered 0.7 μm below the superlattice surface. The implanted region demonstrates reduced photoluminescence intensity relative to the unimplanted regions of the superlattice. The amphoteric nature of silicon and defect‐induced vacancies account for the range and extent of disordering observed in the superlattice.

Band parameters for III–V compound semiconductors and their alloys

Abstract: We present a comprehensive, up-to-date compilation of band parameters for the technologically important III–V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.

Multidimensional quantum well laser and temperature dependence of its threshold current

Abstract: A new type of semiconductor laser is studied, in which injected carriers in the active region are quantum mechanically confined in two or three dimensions (2D or 3D). Effects of such confinements on the lasing characteristics are analyzed. Most important, the threshold current of such laser is predicted to be far less temperature sensitive than that of conventional lasers, reflecting the reduced dimensionality of electronic state. In the case of 3D‐QW laser, the temperature dependence is virtually eliminated. An experiment on 2D quantum well lasers is performed by placing a conventional laser in a strong magnetic field (30 T) and has demonstrated the predicted increase of T0 value from 144 to 313 °C.

Status and Future of High-Power Light-Emitting Diodes for Solid-State Lighting

Abstract: Status and future outlook of III-V compound semiconductor visible-spectrum light-emitting diodes (LEDs) are presented. Light extraction techniques are reviewed and extraction efficiencies are quantified in the 60%+ (AlGaInP) and ~80% (InGaN) regimes for state-of-the-art devices. The phosphor-based white LED concept is reviewed and recent performance discussed, showing that high-power white LEDs now approach the 100-lm/W regime. Devices employing multiple phosphors for "warm" white color temperatures (~3000-4000 K) and high color rendering (CRI>80), which provide properties critical for many illumination applications, are discussed. Recent developments in chip design, packaging, and high current performance lead to very high luminance devices (~50 Mcd/m2 white at 1 A forward current in 1times1 mm2 chip) that are suitable for application to automotive forward lighting. A prognosis for future LED performance levels is considered given further improvements in internal quantum efficiency, which to date lag achievements in light extraction efficiency for InGaN LEDs

Electric field dependence of optical absorption near the band gap of quantum-well structures.

Abstract: We report experiments and theory on the effects of electric fields on the optical absorption near the band edge in GaAs/AlGaAs quantum-well structures. We find distinct physical effects for fields parallel and perpendicular to the quantum-well layers. In both cases, we observe large changes in the absorption near the exciton peaks. In the parallel-field case, the excitons broaden with field, disappearing at fields \ensuremath{\sim}${10}^{4}$ V/cm; this behavior is in qualitative agreement with previous theory and in order-of-magnitude agreement with direct theoretical calculations of field ionization rates reported in this paper. This behavior is also qualitatively similar to that seen with three-dimensional semiconductors. For the perpendicular-field case, we see shifts of the exciton peaks to lower energies by up to 2.5 times the zero-field binding energy with the excitons remaining resolved at up to \ensuremath{\sim}${10}^{5}$ V/cm: This behavior is qualitatively different from that of bulk semiconductors and is explained through a mechanism previously briefly described by us [D. A. B. Miller et al., Phys. Rev. Lett. 53, 2173 (1984)] called the quantum-confined Stark effect. In this mechanism the quantum confinement of carriers inhibits the exciton field ionization. To support this mechanism we present detailed calculations of the shift of exciton peaks including (i) exact solutions for single particles in infinite wells, (ii) tunneling resonance calculations for finite wells, and (iii) variational calculations of exciton binding energy in a field. We also calculate the tunneling lifetimes of particles in the wells to check the inhibition of field ionization. The calculations are performed using both the 85:15 split of band-gap discontinuity between conduction and valence bands and the recently proposed 57:43 split. Although the detailed calculations differ in the two cases, the overall shift of the exciton peaks is not very sensitive to split ratio. We find excellent agreement with experiment with no fitted parameters.