Analytical solutions of the block-diagonalized Hamiltonian for strained wurtzite semiconductors

Kumagai, Masami; Chuang, Shun Lien; Ando, Hiroaki

doi:10.1103/physrevb.57.15303

Cited by 86 publications

(50 citation statements)

References 13 publications

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“…38 Taking into account the expected reduction of piezoelectric response in ultrathin films, we assumed d 33 * = 50 pm/ V. Since the CB deformation potential is unknown for PZT, we used the theoretical value 3 = −4.5 eV obtained in Ref. 39 for wurtzite GaN, which also possesses piezoelectric properties. For the strain sensitivity 33 of the effective mass, we assumed 33 = 10 on the basis of the calculated strain-induced change of the effective mass in wurtzite Ga 0.7 Al 0.3 N. 40 Since 33 is positive, the voltage-induced variations of the effective mass m 3 * and barrier thickness t have a similar effect on the conductance ͓see Eq.…”

Section: ͑3͒mentioning

confidence: 99%

Theoretical current-voltage characteristics of ferroelectric tunnel junctions

et al. 2005

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We present the concept of ferroelectric tunnel junctions ͑FTJs͒. These junctions consist of two metal electrodes separated by a nanometer-thick ferroelectric barrier. The current-voltage characteristics of FTJs are analyzed under the assumption that the direct electron tunneling represents the dominant conduction mechanism. First, the influence of converse piezoelectric effect inherent in ferroelectric materials on the tunnel current is described. The calculations show that the lattice strains of piezoelectric origin modify the currentvoltage relationship owing to strain-induced changes of the barrier thickness, electron effective mass, and position of the conduction-band edge. Remarkably, the conductance minimum becomes shifted from zero voltage due to the piezoelectric effect, and a strain-related resistive switching takes place after the polarization reversal in a ferroelectric barrier. Second, we analyze the influence of an internal electric field arising due to imperfect screening of polarization charges by electrons in metal electrodes. It is shown that, for asymmetric FTJs, this depolarizing-field effect also leads to a considerable change of the barrier resistance after the polarization reversal. However, the symmetry of the resulting current-voltage loop is different from that characteristic of the strain-related resistive switching. The crossover from one to another type of the hysteretic curve, which accompanies the increase of FTJ asymmetry, is described taking into account both the strain and depolarizing-field effects. It is noted that asymmetric FTJs with dissimilar top and bottom electrodes are preferable for the nonvolatile memory applications because of a larger resistance on/off ratio.

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Section: ͑3͒mentioning

confidence: 99%

Theoretical current-voltage characteristics of ferroelectric tunnel junctions

et al. 2005

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“…We now have to compute the exciton in case of the AlN semiconductor for which conduction and valence band dispersion relations have been computed by several groups [20][21][22][23][24][25] using first principle calculation approaches. The anisotropy of hole masses can be represented in the framework of the k.p theory [7,26]. The fundamental valence band of AlN has Γ 7 symmetry [3], its wave functions is mainly built from |Γ the context of sophisticated first principle calculations.…”

Section: Comparison With Experimentsmentioning

confidence: 99%

Quantitative interpretation of the excitonic splittings in aluminum nitride

Gil

Guizal

Felbacq

et al. 2011

Eur. Phys. J. Appl. Phys.

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Abstract.We address the interpretation of the splitting between the ground state excitonic transition which indicates the energy of the lowest direct band gap in AlN bulk films and epilayers, and a 36-38 meV higher energy companion. We demonstrate that this splitting is consistent with the initial interpretation in terms of 1s-2s excitonic splitting by using a calculation of the exciton binding energy which includes mass anisotropy and anisotropy of the dielectric constant. Analytical expressions are proposed to compute the evolution of 1s and 2s excitonic energies using an anisotropy parameter. We show that the values of the dielectric constant that are required to fit the data are ε ⊥ ≈ 8.7 and ε ≈ 10, values different from the couple of values ε ⊥ ≈ 7.33 and ε ≈ 8.45 erroneously obtained after a fitting procedure using a spherical description of the long range Coulomb interaction and the classical textbook n −2 spectrum of the excitonic eigenstates. Starting from now, our values are the recommended ones.

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“…(31). 40 The parameter <Sjp x jX> is also defined where E gðInGaNÞ is the bandgap energy of the quantum well shown in Fig. 9, with parameters Δ 1 , Δ 2 and Δ 3 having linearly interpolated values based on the data from Table 3 r provides the 2D joint density of states in the quantum well structure, with thickness L z and the quantity m r is the reduced effective mass with effective mass contributions from electrons m t e and heavy holes m t hh in the direction perpendicular to the ½0001 or C-axis, for the C1-HH1 transition being evaluated here.…”

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confidence: 99%

“…40,49 The terms α and β represent quantities that are a part of the bases functions j1> −j6> for the block-diagonalized Hamiltonian matrix from Eq. (10) and are defined in Eq.…”

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Design of a high sensitivity emitter-detector avalanche photodiode imager using very high transmittance, back-illuminated, silicon-on-sapphire

Stern

2012

Opt. Eng

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Abstract. We present a detailed design study for a novel solid-state focal plane array of silicon avalanche photodiodes (APDs) using an advanced silicon-on-sapphire substrate incorporating an antireflective bilayer consisting of crystalline aluminum nitride (AlN) and amorphous, non-stoichiometric, silicon rich, silicon nitride (a-SiN X <1.33 ) between the silicon and sapphire. The substrate supports electrical and optical integration of a nearly 100% quantum efficiency, silicon APD capable of operating with wide dynamic range in dual linear or Geiger-mode, with a gallium nitride (GaN) laser diode in each pixel. The APD device and epitaxially grown GaN laser are fabricated within a crystallographically etched silicon mesa. The high resolution 27 μm emitter-detector pixel design enables single photon sensitive, solid-state focal plane arrays (FPAs), with passive and active imaging capability in a single FPA. The square 27 μm emitterdetector pixel achieves SNR > 10 in active detection mode for Lambert surfaces at 20,000 m. IntroductionThere is a growing need in science, industry and medical research for compact, large scale detector arrays capable of imaging with high sensitivity in a passive and active detection mode with detectors providing their own source of short pulse, laser illumination to the area in the scene that is conjugated (using a camera lens for example) back to the respective pixel, providing the laser light pulse. In this design study paper, we demonstrate through detailed calculation means that a novel, back-illuminated photonic device design that optically and electrically integrates a nearly 100% quantum efficiency silicon avalanche photodiode (APD), with a vertical-cavity surface-emitting (VCSEL) gallium nitride (GaN) laser diode in a single pixel will enable imaging with high sensitivity [signal-to-noise ratio ðSNRÞ > 10] near room temperature at −30°C, in an active detection mode for Lambert surfaces at ranges up to 20,000 m.The novel emitter-detector pixel design supports a compact, square 27 μm side length silicon APD detector for high resolution, large scale arrays, with each detector capable of wide dynamic range operation in dual linear or Geigermode for passive and active two-dimensional (2D) and three-dimensional (3D) imaging. The advanced emitterdetector pixel achieves nearly 100% APD detector quantum efficiency at the laser emission wavelength of λ 0 ¼ 370 nm, enabled by a very high transmittance silicon-on-sapphire substrate incorporating an antireflective bilayer of crystalline aluminum nitride (AlN) and amorphous, non-stoichiometric, silicon rich, silicon nitride (a-SiN X<1.33 ) that provides optimal

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Analytical solutions of the block-diagonalized Hamiltonian for strained wurtzite semiconductors

Cited by 86 publications

References 13 publications

Theoretical current-voltage characteristics of ferroelectric tunnel junctions

Theoretical current-voltage characteristics of ferroelectric tunnel junctions

Quantitative interpretation of the excitonic splittings in aluminum nitride

Design of a high sensitivity emitter-detector avalanche photodiode imager using very high transmittance, back-illuminated, silicon-on-sapphire

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