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20 Aug 2001

Volume 79, Issue 8, pp. 1073-1217

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Origin of improved luminescence efficiency after annealing of Ga(In)NAs materials grown by molecular-beam epitaxy

Wei Li, Markus Pessa, Tommy Ahlgren, and James Decker

Appl. Phys. Lett. 79, 1094 (2001); http://dx.doi.org/10.1063/1.1396316 (3 pages) | Cited 73 times

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Positron-annihilation measurements and nuclear reaction analysis [utilizing the 14N(d,p)15N and 14N(d,He)12C reactions] in conjunction with Rutherford backscattering spectrometry in the channeling geometry were used to study the defects in as-grown Ga(In)NAs materials grown by molecular beam epitaxy using a radio-frequency plasma nitrogen source. Our data unambiguously show the existence of vacancy-type defects, which we attribute to Ga vacancies, and nitrogen interstitials in the as-grown nitride–arsenide epilayers. These point defects, we believe, are responsible for the low luminescence efficiency of as-grown Ga(In)NAs materials and the enhanced diffusion process during annealing. © 2001 American Institute of Physics.
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78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
61.72.Cc Kinetics of defect formation and annealing
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis

Quantum beats of free and bound excitons in GaN

K. Kyhm, R. A. Taylor, J. F. Ryan, T. Aoki, M. Kuwata-Gonokami, B. Beaumont, and P. Gibart

Appl. Phys. Lett. 79, 1097 (2001); http://dx.doi.org/10.1063/1.1391411 (3 pages) | Cited 2 times

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We present spectrally resolved and time-integrated four-wave mixing measurements at coherent dynamics of bound excitons in a high-quality GaN epilayer. Coherent excitation, with co-circular polarized light, of the neutral donor-bound excitons (D 0X) and A excitons (XA) results in quantum beats, corresponding to the energy splitting between D 0X and XA. The temperature-dependent dephasing rate is used to deduce the strength of the D 0X-acoustic–phonon interaction via the homogeneous linewidth. © 2001 American Institute of Physics.
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71.35.Gg Exciton-mediated interactions
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
63.20.kk Phonon interactions with other quasiparticles
78.47.-p Spectroscopy of solid state dynamics
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
71.35.Cc Intrinsic properties of excitons; optical absorption spectra

Current-modulated electroluminescence spectroscopy and its application to InGaN single-quantum-well blue and green light-emitting diodes

Takashi Azuhata, Takefumi Homma, Yoshikazu Ishikawa, Shigefusa F. Chichibu, Takayuki Sota, and Takashi Mukai

Appl. Phys. Lett. 79, 1100 (2001); http://dx.doi.org/10.1063/1.1396312 (3 pages) | Cited 1 time

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Current-modulated electroluminescence spectroscopy was developed to investigate the mechanism of the current-induced spectral blueshift in InGaN single-quantum-well blue and green light-emitting diodes. The evidence was obtained that tail states exist in InGaN active layers, and also the blueshift was found to be dominated by the tail-state filling effect. © 2001 American Institute of Physics.
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78.66.Fd III-V semiconductors
78.60.Fi Electroluminescence
85.60.Jb Light-emitting devices

Effects of boron-interstitial silicon clusters on interstitial supersaturation during postimplantation annealing

S. Solmi, L. Mancini, S. Milita, M. Servidori, G. Mannino, and M. Bersani

Appl. Phys. Lett. 79, 1103 (2001); http://dx.doi.org/10.1063/1.1396310 (3 pages) | Cited 15 times

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Boron marker-layer structures have been used to investigate the effects of B doping on the evolution of the implantation damage and of the associated transient enhanced diffusion. The samples were damaged by Si implants at different doses in the range 2×1013–1×1014 cm−2 and annealed at 740 °C for times between 2 s and 4 h. The values of interstitial supersaturation, from the beginning of the annealing up to the complete damage recovery, have been determined for the different Si doses for a given B doping level. Damage removal has been followed by double crystal x-ray diffraction. Our results confirm that the formation of boron-interstitial silicon clusters traps a relevant fraction of the interstitials produced by the implantation. This trapping action gives rise to a strong reduction of the interstitial supersaturation, prevents the interstitial clusters from being transformed in {113} defects and modifies the time evolution of the transient enhanced diffusion. X-ray analyses indicate also that the size of the boron-interstitial silicon clusters remains below 2 nm. © 2001 American Institute of Physics.
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81.05.Cy Elemental semiconductors
66.30.J- Diffusion of impurities
61.72.J- Point defects and defect clusters
61.72.uf Ge and Si
61.72.Cc Kinetics of defect formation and annealing
61.80.Jh Ion radiation effects
61.82.Fk Semiconductors

Pressure-induced amorphization of ZrTiCuNiBe bulk glass-forming alloy

Wei Hua Wang, R. J. Wang, D. Y. Dai, D. Q. Zhao, M. X. Pan, and Y. S. Yao

Appl. Phys. Lett. 79, 1106 (2001); http://dx.doi.org/10.1063/1.1396321 (3 pages) | Cited 19 times

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Zr41Ti14Cu12.5Ni10Be22.5 alloy can be cooled under high pressure (HP) to a bulky glassy state at very low cooling rates. The structure and properties of the bulk metallic glass (BMG) are investigated by differential scanning calorimetry, x-ray diffraction, ultrasonic study, and density measurements. The effects of pressure on the glass formation are discussed from the points of view of nucleation kinetics and thermodynamics. The BMG obtained under HP is in a high-density amorphous state that is different in structure and property from low-density amorphous phase quenched in water. Solidification under HP is a promising way not only for synthesizing BMGs with more densely packed structures and different properties, but also for understanding the glass formation mechanism. © 2001 American Institute of Physics.
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61.43.Fs Glasses
62.50.-p High-pressure effects in solids and liquids
62.65.+k Acoustical properties of solids
81.30.Fb Solidification

Ultrathin PtSi layers patterned by scanned probe lithography

E. S. Snow, P. M. Campbell, M. Twigg, and F. K. Perkins

Appl. Phys. Lett. 79, 1109 (2001); http://dx.doi.org/10.1063/1.1394167 (3 pages) | Cited 6 times

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A process for patterning ultrathin layers of PtSi with high spatial resolution is presented. In this process, scanned probe anodic oxidation is used to pattern a surface oxide layer on a H-passivated Si surface. This oxide pattern prevents the reaction of a deposited Pt film with the underlying Si in the formation of PtSi. The unreacted Pt on the oxide is removed by a selective etch before any annealing. This process greatly reduces lateral diffusion and produces a 2-nm-thick PtSi layer with good electrical properties that maintains the fidelity of the patterned oxide mask. Such nanostructured PtSi films are a good candidate for use in constructing lateral Si-based quantum devices. © 2001 American Institute of Physics.
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81.16.Nd Micro- and nanolithography
85.40.Hp Lithography, masks and pattern transfer
85.35.Ds Quantum interference devices
85.40.Ls Metallization, contacts, interconnects; device isolation
81.16.Ta Atom manipulation
81.16.Pr Micro- and nano-oxidation

High-pressure x-ray diffraction of icosahedral Zr–Al–Ni–Cu–Ag quasicrystals

J. Z. Jiang, K. Saksl, H. Rasmussen, T. Watanuki, N. Ishimatsu, and O. Shimomara

Appl. Phys. Lett. 79, 1112 (2001); http://dx.doi.org/10.1063/1.1394951 (3 pages) | Cited 11 times

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The effect of pressure on the structural stability of icosahedral Zr–Al–Ni–Cu–Ag quasicrystals forming from a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass with a supercooled liquid region of 44 K has been investigated by in situ high-pressure angle-dispersive x-ray powder diffraction at ambient temperature using synchrotron radiation. The icosahedral quasicrystal structure is retained up to the highest hydrostatic pressure used (approximately 28 GPa) and is reversible after decompression. The bulk modulus at zero pressure and its pressure derivative of the icosahedral Zr–Al–Ni–Cu–Ag quasicrystal are 99.10±1.26 GPa and 4.25±0.16, respectively. The compression behavior of different Bragg peaks is isotropic and the full width at half maximum of each peak remains almost unchanged during compression, indicating no anisotropic elasticity and no defects in the icosahedral Zr–Al–Ni–Cu–Ag quasicrystals induced by pressure. © 2001 American Institute of Physics.
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61.44.Br Quasicrystals

Bulk diffusion of microwave plasma activated deuterium into undoped natural diamond

A. Laikhtman, A. Hoffman, and C. Cytermann

Appl. Phys. Lett. 79, 1115 (2001); http://dx.doi.org/10.1063/1.1394169 (3 pages) | Cited 5 times

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In the present work undoped natural (100)-, (111)-, and (110)-oriented diamonds were exposed to microwave deuterium plasma. Secondary ion mass spectroscopy (SIMS) in static mode showed that surface deuterium concentration is the highest for (110) surface and the lowest one for (100)-oriented diamond. SIMS depth profile measurements unambiguously revealed the bulk diffusion of deuterium in the concentration of 1020–1021 atoms/cm3. Relative bulk concentrations of deuterium in the three differently oriented diamonds retained those on the surface. The measured diffusion length of deuterium is ∼0.6 μm. These results support previously performed theoretical calculations and enlighten the data obtained from absolute quantum photoyield measurements of hydrogenated natural diamond recently reported by us. © 2001 American Institute of Physics.
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66.30.J- Diffusion of impurities
81.05.U- Carbon/carbon-based materials
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
52.77.Dq Plasma-based ion implantation and deposition
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
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