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13 Sep 2004

Volume 85, Issue 11, pp. 1871-2145

Issue Cover Spotlight Figure

Appl. Phys. Lett. 85, 1895 (2004); http://dx.doi.org/10.1063/1.1792802 (3 pages)

Markus Deubel, Martin Wegener, Artan Kaso, and Sajeev John
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Light-induced metastability in hydrogenated nanocrystalline silicon solar cells

Baojie Yan, Guozhen Yue, Jessica M. Owens, Jeffrey Yang , and Subhendu Guha

Appl. Phys. Lett. 85, 1925 (2004); http://dx.doi.org/10.1063/1.1790072 (3 pages) | Cited 33 times

Online Publication Date: 17 September 2004

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Light-induced metastability in hydrogenated nanocrystalline silicon (nc-Si:H) single-junction solar cells has been studied under different light spectra. The nc-Si:H studied contains a certain fraction of hydrogenated amorphous silicon (a-Si:H). We observe no light-induced degradation when the photon energy used is lower than the bandgap of a-Si:H, while degradation occurs when the photon energy is higher than the bandgap. We conclude that the light-induced defect generation occurs mainly in the amorphous phase. Light soaking experiments on a-Si:H∕a-SiGe:H∕nc-Si:H triple-junction solar cells show no light-induced degradation in the bottom cell, because the a-Si:H top and a a-SiGe:H middle cells absorb most of the high-energy photons.
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84.60.Jt Photoelectric conversion
78.66.Db Elemental semiconductors and insulators
78.66.Jg Amorphous semiconductors; glasses
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters

Heteroepitaxy of high-quality Ge on Si by nanoscale Ge seeds grown through a thin layer of SiO2

Qiming Li, Ying-Bing Jiang, Huifang Xu, Stephen Hersee, and Sang M. Han

Appl. Phys. Lett. 85, 1928 (2004); http://dx.doi.org/10.1063/1.1790027 (3 pages) | Cited 14 times

Online Publication Date: 17 September 2004

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We demonstrate that high-quality Ge can be grown on Si covered with a thin layer of chemical SiO2. When the oxidized Si substrate is exposed to Ge molecular beam, 7-nm-wide seed pads form in the oxide layer and “touchdown” on the underlying Si. Upon continued exposure, Ge selectively grows on the seed pads rather than on SiO2, and the seeds coalesce to form an epitaxial lateral overgrowth (ELO) layer. The Ge ELO layer is characterized by transmission electron microscopy and etch-pit density (EPD). The Ge ELO layer is free of dislocation network, but stacking faults exist near the Ge-SiO2 interface. A fraction of these stacking faults propagate to the surface, resulting in EPD less than 2×106 cm−2. The high quality Ge ELO layer is attributed to a high density of nanoscale Ge seed pads interspaced by 2–12-nm-wide SiO2 patches.
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68.55.A- Nucleation and growth
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.Nn Stacking faults and other planar or extended defects
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.37.Lp Transmission electron microscopy (TEM)

Below band gap photoreflectance transitions in epitaxial GaN

Phil W. Yu, Jerry D. Clark, David C. Look, C. Q. Chen, Jinwei Yang, Edmundas Koutstis, M. Asif Khan, Denis V. Tsvertkov, and Vladimir A. Dmitriev

Appl. Phys. Lett. 85, 1931 (2004); http://dx.doi.org/10.1063/1.1780602 (3 pages) | Cited 4 times

Online Publication Date: 17 September 2004

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A photoreflectance (PR) and photoluminescence (PL) study has been performed on a Si-doped epitaxial GaN layer that contains impurity or defect related below band gap features in its PR spectrum. In the 300 K PR spectrum, these features appear at energies of 3.26 and 3.33 eV, respectively, but below 180 K they can no longer be seen. The 3.26 eV line evidently corresponds to a donor acceptor pair transition, also seen in PL. The origin of the 3.33 eV line is uncertain, but may correspond to a transition involving the nitrogen vacancy.
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78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
71.55.Eq III-V semiconductors

Laser-induced wavy pattern formation in metal thin films

Ke Xiao, Zi Sheng Guan, Guo Jie Wang, Lei Jiang, Dao Ben Zhu, and Yu Ren Wang

Appl. Phys. Lett. 85, 1934 (2004); http://dx.doi.org/10.1063/1.1787891 (3 pages) | Cited 10 times

Online Publication Date: 17 September 2004

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Laser-induced well-ordered and controllable wavy patterns are constructed in the deposited metal thin film. The micrometer-sized structure and orientation of the wavy patterns can be controlled via scanning a different size of rectangle laser spot on the films. Ordered patterns such as aligned, crossed, and whirled wave structures were designed over large areas. This patterning technique may find applications in both exploring the reliability and mechanical properties of thin films, and fabricating microfluidic devices.
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42.62.-b Laser applications
68.55.-a Thin film structure and morphology
61.82.Bg Metals and alloys
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity

Indirect optical absorption of single crystalline β-FeSi2

Haruhiko Udono, Isao Kikuma, Tsuyoshi Okuno, Yasuaki Masumoto, and Hiroyuki Tajima

Appl. Phys. Lett. 85, 1937 (2004); http://dx.doi.org/10.1063/1.1790590 (3 pages) | Cited 20 times

Online Publication Date: 17 September 2004

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We investigated optical absorption spectra near the fundamental absorption edge of β-FeSi2 single crystals by transmission measurements. The phonon structure corresponding to the emission and absorption component was clearly observed in the low-temperature absorption spectra. Assuming exciton state in the indirect allowed transition, we determined a phonon energy of 0.031±0.004 eV. A value of 0.814 eV was obtained for the exciton transition energy at 4 K.
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78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Fy Semiconductors
78.30.Hv Other nonmetallic inorganics
63.20.D- Phonon states and bands, normal modes, and phonon dispersion
71.35.Cc Intrinsic properties of excitons; optical absorption spectra

Role of N ions in the optical and morphological properties of InGaAsN quantum wells for 1.3–1.5 μm applications

J. Miguel-Sánchez, A. Guzmán, and E. Muñoz

Appl. Phys. Lett. 85, 1940 (2004); http://dx.doi.org/10.1063/1.1790591 (3 pages) | Cited 11 times

Online Publication Date: 17 September 2004

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In this work, we show the effects of N ions coming from a nitrogen plasma source on the optical and structural properties of InGaAsN quantum wells. The presence of ions in the growth chamber was measured by a modified Langmuir probe method at the substrate position. A magnetic field was applied to deflect charged species from the growing surface, producing a lower concentration of ions in the growth surface that led to an improvement of the optical and structural properties of the InGaAsN layers. The samples grown with an applied magnetic field showed a more intense and narrower photoluminescence emission, as well as a lower surface roughness. Additionally, postgrowth annealing has a smaller impact on the photoluminescence emission when a magnetic field is used, and a much lower blueshift is observed.
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68.65.Fg Quantum wells
78.67.De Quantum wells
78.55.Cr III-V semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.Cc Kinetics of defect formation and annealing
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Anharmonic decay of phonons in strain-free wurtzite AlN

J. G. Tischler and J. A. Freitas

Appl. Phys. Lett. 85, 1943 (2004); http://dx.doi.org/10.1063/1.1787957 (3 pages) | Cited 10 times

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We present Raman scattering measurements on high-quality freestanding AlN single crystals. Polarization studies provide clear identification of all allowed phonons. We report the smallest phonon linewidths observed in AlN, which provide a direct measurement of the anharmonic decay of phonons in this material. Also from the Raman mode frequencies and reported index of refraction values we estimated the ordinary and extraordinary dielectric constant values. The calculated values are considerably different from previously reported values of the dielectric constant of AlN.
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63.20.Ry Anharmonic lattice modes
77.22.Ej Polarization and depolarization
78.30.Fs III-V and II-VI semiconductors
77.22.Ch Permittivity (dielectric function)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Recombination dynamics of localized excitons in InGaN quantum dots

T. Bartel, M. Dworzak, M. Strassburg, A. Hoffmann, A. Strittmatter, and D. Bimberg

Appl. Phys. Lett. 85, 1946 (2004); http://dx.doi.org/10.1063/1.1790599 (3 pages) | Cited 28 times

Online Publication Date: 17 September 2004

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Indium-rich fluctuations in ultrathin InGaN layers act at low temperatures as a dense ensemble of quantum dots (QD). This leads to a complex potential landscape with localization sites of widely varying depth for excitons. We report on investigations of the recombination mechanisms of excitons localized in InGaN∕GaN QD structures by time-resolved and spatially resolved photoluminescence (PL) measurements. The structures were grown by metal-organic chemical-vapor deposition on Si (111) substrates. Sharp lines originating from single QDs could be observed. Their PL decays show monoexponential behavior. Similar transition energies have different time constants. Thus, the well-known nonexponential PL decay of the QD ensemble is assigned to the summation of monoexponential decays originating from individual QDs with different exciton lifetimes.
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73.21.La Quantum dots
78.67.Hc Quantum dots
78.47.-p Spectroscopy of solid state dynamics
68.65.Hb Quantum dots (patterned in quantum wells)
81.07.Ta Quantum dots
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.55.Cr III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Mechanical tuning of holographic polymer-dispersed liquid crystal reflection gratings

Scott A. Holmstrom, Lalgudi V. Natarajan, Vincent P. Tondiglia, Richard L. Sutherland, and Timothy J. Bunning

Appl. Phys. Lett. 85, 1949 (2004); http://dx.doi.org/10.1063/1.1790601 (3 pages) | Cited 11 times

Online Publication Date: 17 September 2004

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Holographic polymer-dispersed liquid crystal reflective structures have been formed using a highly elastic photopolymer. The elasticity allows for mechanical tuning of the reflection notch by over 120 nm in the visible spectral range using compressive stress. The shift in the central position of the reflection notch is related to the strain in the system and an effective elastic modulus for the structure is obtained.
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42.70.Df Liquid crystals
42.70.Jk Polymers and organics
42.40.Eq Holographic optical elements; holographic gratings
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
78.40.Me Organic compounds and polymers
62.10.+s Mechanical properties of liquids
61.30.Pq Microconfined liquid crystals: droplets, cylinders, randomly confined liquid crystals, polymer dispersed liquid crystals, and porous systems

Arrays of wirelike microstructures of Ag with visible wavelength transparent plasmonic response at near-ultraviolet and midinfrared regions

A. Biswas, R. Kunz, O. C. Aktas, M. Elbahri, R. Adelung, H. Takele, U. Saeed, U. Schürmann, V. Zaporojtchenko, and F. Faupel

Appl. Phys. Lett. 85, 1952 (2004); http://dx.doi.org/10.1063/1.1788895 (3 pages) | Cited 1 time

Online Publication Date: 17 September 2004

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We present a simple masked thermal evaporation technique to fabricate arrays of wirelike Ag microstructures of width 8 μm with an extremely high aspect ratio on either silicon or glass substrates. In accordance with the theory of periodic arrays of thin wires, the electromagnetic response of Ag microstructures has shown a characteristic low-frequency plasmonic behavior with a transparent visible region. Plasmon absorption is observed to be splitted largely into transverse and predominating longitudinal bands at near-ultraviolet (415 nm) and midinfrared wavelengths (2867 nm), corresponding to the oscillation of the free electrons perpendicular to and along the long axis of the wires.
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81.05.Bx Metals, semimetals, and alloys
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
78.40.Kc Metals, semimetals, and alloys
78.30.Er Solid metals and alloys
78.66.Bz Metals and metallic alloys

Hydrogen dilution profiling for hydrogenated microcrystalline silicon solar cells

Baojie Yan, Guozhen Yue, Jeffrey Yang, Subhendu Guha, D. L. Williamson, Daxing Han, and Chun-Sheng Jiang

Appl. Phys. Lett. 85, 1955 (2004); http://dx.doi.org/10.1063/1.1788877 (3 pages) | Cited 28 times

Online Publication Date: 17 September 2004

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The structural properties of hydrogenated microcrystalline silicon solar cells are investigated using Raman, x-ray diffraction, and atomic force microscopy. The experimental results showed a significant increase of microcrystalline volume fraction and grain size with increasing film thickness. The correlation between the cell performance and the microstructure suggests that the increase of grain size and microcrystalline volume fraction with thickness is the main reason for the deterioration of cell performance as the intrinsic layer thickness increases. By varying the hydrogen dilution in the gas mixture during deposition, microstructure evolution has been controlled and cell performance significantly improved.
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84.60.Jt Photoelectric conversion
78.66.Db Elemental semiconductors and insulators
81.05.Cy Elemental semiconductors
78.66.Jg Amorphous semiconductors; glasses
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
82.30.-b Specific chemical reactions; reaction mechanisms
52.77.Dq Plasma-based ion implantation and deposition
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.37.Ps Atomic force microscopy (AFM)

Effects of Ti–W codoping on the optical and electrical switching of vanadium dioxide thin films grown by a reactive pulsed laser deposition

M. Soltani, M. Chaker, E. Haddad, R. V. Kruzelecky, and J. Margot

Appl. Phys. Lett. 85, 1958 (2004); http://dx.doi.org/10.1063/1.1788883 (3 pages) | Cited 44 times

Online Publication Date: 17 September 2004

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Thin films of thermochromic VO2, V1−xWxO2 and V1−x−yWxTiyO2 (x=0.014, and y=0.12) were synthesized onto quartz substrates using a reactive pulsed laser deposition technique. The films were then characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The W and Ti dopant effects on the semiconductor-to-metal phase transition of VO2 were investigated by measuring the temperature dependence of their electrical resistivity and their infrared transmittance. Remarkably strong effects of Ti–W codoping were observed on both the optical and electrical properties of V1−x−yWxTiyO2 films. The IR transmittance was improved, while the transition temperature could be varied from 36°C for W-doped VO2 film to 60°C for Ti–W codoped VO2 film. In addition, at room temperature, a higher temperature coefficient of resistance of 5.12%∕°C is achieved. Finally, both optical and electrical hysteresis are completely suppressed by Ti–W codoping the VO2 films.
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68.55.A- Nucleation and growth
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
71.30.+h Metal-insulator transitions and other electronic transitions
78.66.Nk Insulators
79.60.Bm Clean metal, semiconductor, and insulator surfaces
81.15.Fg Pulsed laser ablation deposition
78.30.Am Elemental semiconductors and insulators
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.S- Impurities in crystals

Compositional dependence of phase separation in InGaN layers

M. Rao, D. Kim, and S. Mahajan

Appl. Phys. Lett. 85, 1961 (2004); http://dx.doi.org/10.1063/1.1791327 (3 pages) | Cited 28 times

Online Publication Date: 17 September 2004

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Phase separation in InGaN layers grown by metalorganic chemical vapor deposition on GaN epilayers was investigated using transmission electron microscopy. Layer thicknesses of 220 and 660 nm were deposited with InN fractions ranging from 3% to 34%. At InN contents of 3%, plan-view TEM images show a homogeneous microstructure and selected area diffraction (SAD) patterns exhibit no evidence of satellite spots. InN contents of 12% result in a speckled contrast. Satellites close to the fundamental spots belonging to the wurtzite structure are present in SAD patterns and they are indicative of composition modulations lying in the (0001) growth plane. No satellites are observed along the [0001] direction, implying that phase separation is two-dimensional in nature. Samples containing InN fractions of between 22% and 28% have microstructures exhibiting much stronger contrast variations. Satellite spots in SAD patterns are further spaced from the fundamental reflections. This trend continues on increasing InN content to 34%. In addition, cross-sectional TEM images show an absence of contrast from InGaN layers with InN contents above 12%, in the vicinity of the InGaN∕GaN interface, indicating that coherency strain inhibits phase separation. Arguments are developed to rationalize these observations.
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81.05.Ea III-V semiconductors
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
64.75.-g Phase equilibria
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.37.Lp Transmission electron microscopy (TEM)

Structural and optical properties of Ba(Cox,Ti1−x)O3 thin films fabricated by sol-gel process

Y. W. Li, J. L. Sun, X. J. Meng, J. H. Chu, and W. F. Zhang

Appl. Phys. Lett. 85, 1964 (2004); http://dx.doi.org/10.1063/1.1786654 (3 pages) | Cited 6 times

Online Publication Date: 17 September 2004

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Ba(Cox,Ti1−x)O3 thin films were prepared on fused quartz substrate by a sol-gel method. The results of x-ray diffraction showed that the films are perovskite phase and the change of lattice constant caused by different Co concentration is undetectable. Optical transmittance measurement indicated that Co doping has effect on the energy band structure. The energy gap of Ba(Cox,Ti1−x)O3 decreased linearly with the increase of Co concentration. It is inferred that the energy level of conduction bands decline with the Co content increasing. This result is similar to the phenomena found in binary semiconductor where the band gap decreases with the increasing of average atomic number.
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77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
78.66.Nk Insulators
81.10.Dn Growth from solutions
81.10.Fq Growth from melts; zone melting and refining
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
77.80.-e Ferroelectricity and antiferroelectricity
61.72.S- Impurities in crystals
68.55.-a Thin film structure and morphology
71.20.Ps Other inorganic compounds
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.30.Hv Other nonmetallic inorganics
68.55.A- Nucleation and growth

Structural evolution of dislocation half-loops in epitaxial BaTiO3 thin films during high-temperature annealing

H. P. Sun, X. Q. Pan, J. H. Haeni, and D. G. Schlom

Appl. Phys. Lett. 85, 1967 (2004); http://dx.doi.org/10.1063/1.1789233 (3 pages) | Cited 10 times

Online Publication Date: 17 September 2004

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BaTiO3 thin films were grown on (001) SrTiO3 by reactive molecular beam epitaxy. Transmission electron microscopy studies showed that there is a high density of dislocation half-loops inside 8- and 12-nm-thick films. By thermal annealing at 1000°C, the isolated small dislocation half-loops grow and combine to form a self-assembled regular dislocation network at the film/substrate interface. Threading dislocations in the films are removed and the lattice mismatch strain in the film is nearly completely relaxed by annealing at high temperature.
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68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.37.Lp Transmission electron microscopy (TEM)
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.40.Gh Other heat and thermomechanical treatments
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Crack-free and conductive Si-doped AlN∕GaN distributed Bragg reflectors grown on 6H-SiC(0001)

Tommy Ive, Oliver Brandt, Helmar Kostial, Thorsten Hesjedal, Manfred Ramsteiner, and Klaus H. Ploog

Appl. Phys. Lett. 85, 1970 (2004); http://dx.doi.org/10.1063/1.1791738 (3 pages) | Cited 22 times

Online Publication Date: 17 September 2004

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We demonstrate Si-doped n-type AlN∕GaN distributed Bragg reflectors grown on 6H-SiC(0001). The structures are crack-free and have a stopband centered around 450 nm with a full width at half maximum between 40 and 50 nm. The maximum measured reflectance is ⩾99%. A comparison between Si-doped and undoped structures reveals no degradation of the reflectance due to the Si doping. Vertical conductance measurements at room temperature on the samples show an ohmic I–V behavior in the entire measurement range. The measured resistivity at 77 K is only a factor of 2 larger than the resistivity measured at room temperature.
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81.05.Ea III-V semiconductors
42.79.Bh Lenses, prisms and mirrors
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.S- Impurities in crystals
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
61.72.uj III-V and II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.30.Fs III-V and II-VI semiconductors

Lack of the critical pressure for weakening of size-induced stiffness in 3C–SiC nanocrystals under hydrostatic compression

Haozhe Liu, Jingzhu Hu, Jinfu Shu, Daniel Häusermann, and Ho-kwang Mao

Appl. Phys. Lett. 85, 1973 (2004); http://dx.doi.org/10.1063/1.1789240 (3 pages) | Cited 17 times

Online Publication Date: 17 September 2004

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Using in situ high-pressure x-ray diffraction methods, the compressibility of 30 nm 3C–SiC nanocrystals was studied under hydrostatic conditions while helium was used as pressure transmitting medium, as well as under nonhydrostatic conditions without pressure medium. No threshold pressure phenomenon was observed for the compressibility of the nanocrystals during compression in hydrostatic conditions, while the critical pressure around 10.5 GPa was observed during nonhydrostatic compression. These indicate that the threshold pressure phenomena, recently reported that the nanocrystals initially exhibited much higher bulk modulus below the threshold pressure during compression [Appl. Phys. Lett. 83, 3174 (2003); J. Phys. Chem. 107, 14151 (2003)], were mainly caused by the nonhydrostatic effect instead of a specific feature of nanocrystals upon compression. The bulk modulus of 3C–SiC nanocrystals is estimated as 220.6±0.6 GPa based on the hydrostatic compression data.
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62.50.-p High-pressure effects in solids and liquids
62.25.-g Mechanical properties of nanoscale systems
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
81.40.Vw Pressure treatment

Direct evidence for selective impurity incorporation at the crystal domain boundaries in epitaxial ZnO layers

F. Bertram, D. Forster, J. Christen, N. Oleynik, A. Dadgar, and A. Krost

Appl. Phys. Lett. 85, 1976 (2004); http://dx.doi.org/10.1063/1.1791746 (3 pages) | Cited 6 times

Online Publication Date: 17 September 2004

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A direct correlation of structural properties with the spatial distribution of bound exciton luminescence in ZnO epitaxial layers has been achieved on a microscopic scale using highly spatially and spectrally resolved cathodoluminescence. The morphology of the high quality ZnO layer is characterized by a distinct domain structure. While the laterally integrated cathodoluminescence spectrum shows narrow (full width at half maximum <3 meV) I8 luminescence, a pronounced emission line at I0∕I1 emerges in the local spectra taken at domain boundaries. In complete contrast, no I0∕I1 emission is found inside the domains. Monochromatic images further evidence the selective incorporation of impurities at the grain boundaries of domains. Micro mappings of the I8 peak wavelength directly visualize the strain relaxation across the domains toward their very center, where a drop in quantum efficiency indicates enhanced defect concentration.
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81.05.Dz II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
71.55.Gs II-VI semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.S- Impurities in crystals
78.66.Hf II-VI semiconductors
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
78.60.Hk Cathodoluminescence, ionoluminescence
71.35.-y Excitons and related phenomena
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
68.60.Bs Mechanical and acoustical properties

Differential Hall effect profiling of ultrashallow junctions in Sb implanted silicon

T. Alzanki, R. Gwilliam, N. Emerson, and B. J. Sealy

Appl. Phys. Lett. 85, 1979 (2004); http://dx.doi.org/10.1063/1.1792378 (2 pages) | Cited 9 times

Online Publication Date: 17 September 2004

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A differential Hall effect technique has been developed to obtain doping profiles at a depth resolution down to 2 nm with junction depths of about 20 nm. We have determined the electrical characteristics of 5×1014 Sb+ cm−2 implanted in (100) silicon at an energy of 5 keV. A comparison was made between carrier concentration profiles and secondary ion mass spectroscopy measurements of the atomic profiles as a function of annealing temperature. We have profiled single energy implants of antimony and also double implants; the latter enables complete profiles to be measured down to the background level of about 1018 cm−3.
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61.72.uf Ge and Si
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Cw Elemental semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
81.05.Cy Elemental semiconductors
61.72.S- Impurities in crystals
61.80.Jh Ion radiation effects
81.40.Gh Other heat and thermomechanical treatments

Critical effects of substrate terraces and steps morphology on the growth mode of epitaxial SrRuO3 films

F. Sánchez, G. Herranz, I. C. Infante, J. Fontcuberta, M. V. García-Cuenca, C. Ferrater, and M. Varela

Appl. Phys. Lett. 85, 1981 (2004); http://dx.doi.org/10.1063/1.1786361 (3 pages) | Cited 20 times

Online Publication Date: 17 September 2004

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We report on the controlled fabrication of the arrays of self-organized fingerlike nanostructures of SrRuO3 that form on SrTiO3(001). We show that the size (width and height) of the one-dimensional nanometric units can be tuned or suppressed by using appropriate substrate vicinality θv and surface termination. Critical effects on the fingers height are observed when θv is below an angle as small as ∼0.1°. The value of θv also determines if the final two-dimensional growth is by a step flow (θv=0.5°), by layer by layer (θv=0.04°), or by coexistence of both mechanisms (θv=0.1°). The fingers are suppressed when TiO2-terminated low-miscut substrates are used, as film nucleation takes place on the terraces and then substrate steps are not active as templates for the one-dimensional structure formation. These findings shall contribute to progress toward lateral nanostructuration of complex oxide surfaces.
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81.07.Bc Nanocrystalline materials
61.46.-w Structure of nanoscale materials
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Fg Pulsed laser ablation deposition
81.16.Dn Self-assembly
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