APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

18 Aug 2008

Volume 93, Issue 7, Articles (07xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 93, 073101 (2008); http://dx.doi.org/10.1063/1.2970055 (3 pages)

A. J. Du, Y. Chen, G. Q. Lu, and Sean C. Smith
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Ultrathin SiO2 layer on atomically flat Si(111) surfaces with excellent electrical characteristics formed by nitric acid oxidation method

Woo-Byoung Kim, Asuha, Taketoshi Matsumoto, and Hikaru Kobayashi

Appl. Phys. Lett. 93, 072101 (2008); http://dx.doi.org/10.1063/1.2970040 (3 pages) | Cited 6 times

Online Publication Date: 18 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have developed a method of formation of atomically smooth Si/SiO2 interfaces by oxidation of atomically flat Si(111) surfaces by use of azeotropic nitric acid (HNO3) aqueous solutions (i.e., 68 wt % HNO3 at 121 °C). For the SiO2 layer on the atomically smooth Si substrates, the concentration of suboxide species, Si2+, is ∼ 50% of that on the rough Si substrates, and the valence band discontinuity is higher by ∼ 0.1 eV. In this case, the leakage current flowing through the ∼ 1.2 nm SiO2 is low, and further decreased by postmetallization annealing at 250 °C in hydrogen (e.g., 0.5 A/cm2 at VG = 1 V).
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
81.65.Mq Oxidation
61.72.Cc Kinetics of defect formation and annealing

Broadband electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor

L. H. Willems van Beveren, H. Huebl, D. R. McCamey, T. Duty, A. J. Ferguson, R. G. Clark, and M. S. Brandt

Appl. Phys. Lett. 93, 072102 (2008); http://dx.doi.org/10.1063/1.2960356 (3 pages) | Cited 13 times

Online Publication Date: 19 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor. An on-chip transmission line is used to generate the oscillating magnetic field allowing broadband operation. At millikelvin temperatures, continuous wave spectra were obtained up to 40 GHz, using both magnetic field and microwave frequency modulation. The spectra reveal the hyperfine-split electron spin resonances characteristic for Si:P and a central feature which displays the fingerprint of spin-spin scattering in the two-dimensional electron gas.
Show PACS
76.30.Lh Other ions and impurities
85.75.Hh Spin polarized field effect transistors

Low Schottky barrier height for silicides on n-type Si (100) by interfacial selenium segregation during silicidation

Hoong-Shing Wong, Lap Chan, Ganesh Samudra, and Yee-Chia Yeo

Appl. Phys. Lett. 93, 072103 (2008); http://dx.doi.org/10.1063/1.2970958 (3 pages) | Cited 13 times

Online Publication Date: 20 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electron Schottky barrier height ΦBn modulation for NiSi and PtSi formed on selenium-implanted n-type Si (100) has been experimentally investigated. Selenium (Se) segregation is observed at the silicide/n-Si(100) interface during silicidation process. ΦBn of 83 and 120 meV were achieved for Se segregated NiSi and PtSi on n-Si (100) interfaces, respectively. Contrary to previously reported Fermi level depinning effect in monolayer Se-passivated n-Si (100), the low ΦBn achieved in this work points to metal silicide Fermi level pinning near to conduction band EC of n-Si (100).
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
71.20.Mq Elemental semiconductors

Influence of top surface passivation on bottom-channel hole mobility of ultrathin SiGe- and Ge-on-insulator

Haigui Yang, Dong Wang, Hiroshi Nakashima, Hongye Gao, Kana Hirayama, Ken-ichi Ikeda, Satoshi Hata, and Hideharu Nakashima

Appl. Phys. Lett. 93, 072104 (2008); http://dx.doi.org/10.1063/1.2972114 (3 pages) | Cited 9 times

Online Publication Date: 20 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Bottom-channel hole mobility was examined by a pseudo-metal-oxide-semiconductor field-effect transistors method for ultrathin SiGe-on-insulator (SGOI) and Ge-on-insulator (GOI), which were fabricated using Ge condensation by dry oxidation. By comparing samples with and without a top SiO2 layer, we investigated the influence of top surface passivation on bottom-channel hole mobility. Mobility degradation was found in an ultrathin SGOI/GOI layer without top SiO2 and became more serious with a decrease in the thickness of the SGOI/GOI layer, which strongly suggested that top surface passivation is necessary to evaluate accurate channel mobility. A 13-nm-thick GOI with passivation showed a high mobility value of 440 cm2/V s.
Show PACS
85.30.Tv Field effect devices

1,8-octanedithiol as a processing additive for bulk heterojunction materials: Enhanced photoconductive response

Nelson E. Coates, In-Wook Hwang, Jeffrey Peet, Guillermo C. Bazan, Daniel Moses, and Alan J. Heeger

Appl. Phys. Lett. 93, 072105 (2008); http://dx.doi.org/10.1063/1.2969405 (3 pages) | Cited 15 times

Online Publication Date: 20 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present measurements of steady state and transient (τ<70 ps) photoconductivity of the low bandgap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] mixed with [6,6]-phenyl C71-butyric acid methyl ester films processed with and without the 1,8-octanedithiol additive. The data demonstrate enhanced photoconductive response in the bulk heterojunction material processed with the additive. The increase results primarily from enhanced carrier mobility and to a lesser extent from a more efficient photogeneration of mobile carriers and longer mobile carrier lifetimes. The enhanced photoresponse is consistent with the increase in power conversion efficiency obtained from solar cells in which the bulk heterojunction film is processed using 1,8-octanedithiol.
Show PACS
73.50.Pz Photoconduction and photovoltaic effects
72.40.+w Photoconduction and photovoltaic effects
73.50.Dn Low-field transport and mobility; piezoresistance
72.80.Le Polymers; organic compounds (including organic semiconductors)
73.61.Ph Polymers; organic compounds

Anisotropic hole-mass tensor of CuIn1−xGax(S,Se)2: Presence of free carriers narrows the energy gap

Clas Persson

Appl. Phys. Lett. 93, 072106 (2008); http://dx.doi.org/10.1063/1.2969467 (3 pages) | Cited 11 times

Online Publication Date: 20 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Analysis of the band edges of CuIn1−xGax(S,Se)2 with x = 0.0, 0.5, and 1.0 reveals that (i) CuIn1−xGaxS2 has larger effective electron mc and hole mv masses than CuIn1−xGaxSe2; (ii) whereas Ga content affects band curvatures only slightly, the sign of the crystal-field split Δcf as well as the spin-orbit coupling affect mv strongly; (iii) the optical response ε2(ℏω) is comparable for all six compounds; and (iv) band filling of electrons (n = 1019 cm−3) and holes (p = n) narrows the band gap by Eg ≈ Eg0−0.1 eV and generates an optical band gap of Egopt ≈ Eg+0.2 eV.
Show PACS
71.20.Nr Semiconductor compounds
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
71.70.Ch Crystal and ligand fields
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Effect of carbon codoping on boron diffusion in amorphous silicon

L. A. Edelman, S. Jin, K. S. Jones, R. G. Elliman, and L. M. Rubin

Appl. Phys. Lett. 93, 072107 (2008); http://dx.doi.org/10.1063/1.2975833 (3 pages) | Cited 2 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of carbon codoping on boron diffusion in amorphous silicon is investigated during low temperature annealing. The diffusivity of boron is unaffected by carbon codoping, but the fraction of mobile boron is observed to increase with increasing carbon concentration. A concomitant reduction in boron clustering is also observed at higher carbon coimplant concentrations, consistent with a change in the local trap concentration. This is consistent with carbon possibly acting as a trap site for boron and thereby changing the size and dynamics of the boron cluster formation.
Show PACS
68.35.Fx Diffusion; interface formation
61.72.uf Ge and Si

Relaxation of strained silicon on Si0.5Ge0.5 virtual substrates

J. Parsons, R. J. H. Morris, D. R. Leadley, E. H. C. Parker, D. J. F. Fulgoni, and L. J. Nash

Appl. Phys. Lett. 93, 072108 (2008); http://dx.doi.org/10.1063/1.2975188 (3 pages) | Cited 5 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strain relaxation has been studied in tensile strained silicon layers grown on Si0.5Ge0.5 virtual substrates, for layers many times the critical thickness, using high resolution x-ray diffraction. Layers up to 30 nm thick were found to relax less than 2% by the glide of preexisting 60° dislocations. Relaxation is limited because many of these dislocations dissociate into extended stacking faults that impede the dislocation glide. For thicker layers, nucleated microtwins were observed, which significantly increased relaxation to 14%. All these tensile strained layers are found to be much more stable than layers with comparable compressive strain.
Show PACS
81.05.Cy Elemental semiconductors
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
61.72.Mm Grain and twin boundaries
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity

Room temperature hydrogen detection using Pd-coated GaN nanowires

Wantae Lim, J. S. Wright, B. P. Gila, Jason L. Johnson, Ant Ural, Travis Anderson, F. Ren, and S. J. Pearton

Appl. Phys. Lett. 93, 072109 (2008); http://dx.doi.org/10.1063/1.2975173 (3 pages) | Cited 28 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Multiple GaN nanowires produced by thermal chemical vapor deposition were employed as gas sensors for detection of hydrogen at concentrations from 200–1500 ppm in N2 at 300 K. Palladium coating of the wires improved the sensitivity by a factor of up to 11 at low ppm concentrations relative to uncoated controls. The GaN nanowires showed relative responses of ∼ 7.4% at 200 ppm and ∼ 9.1% at 1500 ppm H2 in N2 after a 10 min exposure. Upon removal of hydrogen from the measurement ambient, ∼ 90% of the initial GaN conductance was recovered within 2 min. Temperature dependent measurements showed a larger relative response and shorter response time at elevated temperature. The adsorption activation energy of the sensor was 2.2 kcal mol−1 at 3000 ppm H2 in N2. These sensors exhibit low power consumption (<0.6 mW) at 300 K.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.35.-p Nanoelectronic devices

Valence band offset of MgO/4H-SiC heterojunction measured by x-ray photoelectron spectroscopy

B. L. Zhang, F. F. Cai, G. S. Sun, H. B. Fan, P. F. Zhang, H. Y. Wei, X. L. Liu, S. Y. Yang, Q. S. Zhu, and Z. G. Wang

Appl. Phys. Lett. 93, 072110 (2008); http://dx.doi.org/10.1063/1.2975168 (3 pages) | Cited 6 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The valence band offset (VBO) of MgO(111)/4H-SiC heterojunction has been directly measured by x-ray photoelectron spectroscopy. The VBO is determined to be 3.65±0.23 eV and the conduction band offset is deduced to be 0.92±0.23 eV, indicating that the heterojunction has a type-I band alignment. The accurate determination of the valence and conduction band offsets is important for the applications of MgO/SiC optoelectronic devices.
Show PACS
73.20.At Surface states, band structure, electron density of states
79.60.-i Photoemission and photoelectron spectra

Zn- and O-face polarity effects at ZnO surfaces and metal interfaces

Yufeng Dong, Z-Q. Fang, D. C. Look, G. Cantwell, J. Zhang, J. J. Song, and L. J. Brillson

Appl. Phys. Lett. 93, 072111 (2008); http://dx.doi.org/10.1063/1.2974983 (3 pages) | Cited 21 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Depth-resolved cathodoluminescence spectroscopy, current-voltage, capacitance-voltage, and deep level transient spectroscopy of ZnO (0001) Zn- and (000math) O-polar surfaces and metal interfaces show systematically higher Zn-face near band edge emission and lower near-surface defect emission. Even with remote plasma decreases of the 2.5 eV near-surface defect emission, (0001)-Zn face emission quality still exceeds that of (000math)-O face. Ultrahigh vacuum-deposited Au and Pd diodes on as-received and O2/He plasma-cleaned surfaces display a strong polarity dependence that correlates with defect emissions, traps, and interface chemistry. A comprehensive model accounts for the polarity-dependent transport properties and their correlations with carrier concentration profiles.
Show PACS
71.55.Gs II-VI semiconductors
78.60.Hk Cathodoluminescence, ionoluminescence
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Capacitance characteristics of phase separated La0.5Ca0.5MnO3/Nb–SrTiO3 p-n junction

B. T. Xie, Y. G. Zhao, and C. M. Xiong

Appl. Phys. Lett. 93, 072112 (2008); http://dx.doi.org/10.1063/1.2973904 (3 pages) | Cited 6 times

Online Publication Date: 22 August 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The capacitance characteristics of La0.5Ca0.5MnO3/Nb–SrTiO3 p-n junction and magnetic property have been investigated. The magnetic field-induced increase in ferromagnetic metallic phase, irreversibility, and the exchange bias effect were observed. The junction also shows a remarkable thermal hysteresis of capacitance, a giant positive magnetocapacitance (MC), a remarkable difference of MC for the zero field cooling and field cooling processes, and a memory effect of magnetic field. The results can be understood in terms of phase separation. This work demonstrates the remarkable tunability of the capacitance for phase separated manganite heterojunctions, which may have potential applications.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
64.75.-g Phase equilibria
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close