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

13 Dec 2010

Volume 97, Issue 24, Articles (24xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 97, 241101 (2010); http://dx.doi.org/10.1063/1.3525583 (3 pages)

Kanghee Lee and Jaewook Ahn
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Thermoelectric-induced spin currents in single-molecule magnet tunnel junctions

Zhengzhong Zhang, Liang Jiang, Ruiqiang Wang, Baigeng Wang, and D. Y. Xing

Appl. Phys. Lett. 97, 242101 (2010); http://dx.doi.org/10.1063/1.3525571 (3 pages) | Cited 2 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A molecular spin-current generator is proposed, which consists of a single-molecule magnet (SMM) coupled to two normal metal electrodes with temperature gradient. It is shown that this tunneling junction can generate a highly spin-polarized current by thermoelectric effects, whose flowing direction and spin polarization can be changed by adjusting the gate voltage applied to the SMM. This device can be realized with current technologies and may have practical use in spintronics and quantum information.
Show PACS
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
85.65.+h Molecular electronic devices

Fundamental oscillation of resonant tunneling diodes above 1 THz at room temperature

Safumi Suzuki, Masahiro Asada, Atsushi Teranishi, Hiroki Sugiyama, and Haruki Yokoyama

Appl. Phys. Lett. 97, 242102 (2010); http://dx.doi.org/10.1063/1.3525834 (3 pages) | Cited 9 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fundamental oscillations up to 1.04 THz were achieved in resonant tunneling diodes at room temperature. A graded emitter and thin barriers were introduced in GaInAs/AlAs double-barrier resonant tunneling diodes for reductions of the transit time in the collector depletion region and the resonant tunneling time, respectively. Output powers were 7 μW at 1.04 THz and around 10 μW in 0.9–1 THz region. A change in oscillation frequency of about 4% with bias voltage was also obtained.
Show PACS
84.40.-x Radiowave and microwave (including millimeter wave) technology
85.30.Kk Junction diodes
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

Temperature dependence of current-voltage characteristics of Ni–AlGaN/GaN Schottky diodes

Wantae Lim, Jae-Hyun Jeong, Jae-Hoon Lee, Seung-Bae Hur, Jong-Kyu Ryu, Ki-Se Kim, Tae-Hyung Kim, Sang Yeob Song, Jong-In Yang, and S. J. Pearton

Appl. Phys. Lett. 97, 242103 (2010); http://dx.doi.org/10.1063/1.3525931 (3 pages) | Cited 5 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ni–AlGaN/GaN Schottky barrier diodes (SBDs) with lateral geometry were fabricated on sapphire substrates. At 300 K, devices with 500-μm-diameter Schottky contacts exhibited breakdown voltage (VB) of 765 V, forward current (IF) of 0.065 A at 1.5 V, and specific on-resistance (Ron) of 81.3 mΩ cm2, producing a figure-of-merit (VB2/Ron) of ∼ 7.2 MW cm−2. Measured in multifinger patterns, the same parameters were 420 V, 3.2 A, 4.6 mΩ cm2, and 38.4 MW cm−2, respectively, at 300 K. With the increase in measurement temperature from 300 to 450 K, SBDs with dimensions of 3000×3000 μm2 showed larger effective barrier heights (0.8 eV at 300 K and 1.27 eV at 475 K) and a slightly negative temperature coefficient (−0.48 V K−1) for reverse breakdown voltage, while there was a little change in reverse leakage current. These results show the strong influence of barrier height inhomogeneity on the temperature dependence of apparent barrier heights obtained through current-voltage measurements.
Show PACS
73.40.Ns Metal-nonmetal contacts
85.30.Hi Surface barrier, boundary, and point contact devices
85.30.Kk Junction diodes
73.30.+y Surface double layers, Schottky barriers, and work functions

Direct imaging of boron segregation to extended defects in silicon

S. Duguay, T. Philippe, F. Cristiano, and D. Blavette

Appl. Phys. Lett. 97, 242104 (2010); http://dx.doi.org/10.1063/1.3526376 (3 pages) | Cited 4 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicon was implanted with a high boron dose (5×1015 at. cm−2) at 30 keV and further annealed at 950 °C for 30 s. The sample was analyzed using transmission electron microscopy (TEM) and atom probe tomography (APT). TEM images revealed the presence of a high density of dislocation loops ( ∼ 1011/cm−2) distributed around the projected range of implanted atoms. APT reconstructions showed local enrichment of boron in the form of loops that were interpreted as Cottrell atmosphere. Boron enriched rods, interpreted as the {113} defects, were also observed. Segregation energies of boron atoms to these defects were estimated to be ∼ 0.35 eV.
Show PACS
81.05.Cy Elemental semiconductors
61.72.uf Ge and Si
61.72.Cc Kinetics of defect formation and annealing
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.72.sh Impurity distribution
61.72.Nn Stacking faults and other planar or extended defects

Band structures of graphene hexagonal lattice semiconductor quantum dots

Juan Peng and Shu-Shen Li

Appl. Phys. Lett. 97, 242105 (2010); http://dx.doi.org/10.1063/1.3526724 (3 pages) | Cited 2 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electronic structures of coupled semiconductor quantum dots (QDs) arranged as graphene hexagonal lattice are studied theoretically using the tight-binding method. In our calculations, the electrons can hop to the third-nearest-neighbors, and the overlap matrix as well as the multicenter integral are taken into account. The novel two-dimensional Dirac-like electronic excitations in graphene are found in these artificial planar QD structures. The results provide the theoretical basis for searching Dirac fermions in QD materials and have great significance for investigating and making semiconductor QD devices.
Show PACS
73.22.Pr Electronic structure of graphene
73.21.La Quantum dots
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)
73.20.At Surface states, band structure, electron density of states

Nonlinear electrical properties of Si three-terminal junction devices

Fantao Meng, Jie Sun, Mariusz Graczyk, Kailiang Zhang, Mika Prunnila, Jouni Ahopelto, Peixiong Shi, Jinkui Chu, Ivan Maximov, and H. Q. Xu

Appl. Phys. Lett. 97, 242106 (2010); http://dx.doi.org/10.1063/1.3526725 (3 pages) | Cited 2 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter reports on the realization and characterization of silicon three-terminal junction devices made in a silicon-on-insulator wafer. Room temperature electrical measurements show that the fabricated devices exhibit pronounced nonlinear electrical properties inherent to ballistic electron transport in a three-terminal ballistic junction (TBJ) device. The results show that room temperature functional TBJ devices can be realized in a semiconductor material other than high-mobility III-V semiconductor heterostructures and provide a simple design principle for compact silicon devices in nanoelectronics.
Show PACS
85.30.De Semiconductor-device characterization, design, and modeling

Distinguishing impurity concentrations in GaAs and AlGaAs using very shallow undoped heterostructures

W. Y. Mak, K. Das Gupta, H. E. Beere, I. Farrer, F. Sfigakis, and D. A. Ritchie

Appl. Phys. Lett. 97, 242107 (2010); http://dx.doi.org/10.1063/1.3522651 (3 pages) | Cited 3 times

Online Publication Date: 13 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have developed a method of fabricating very shallow, gateable, undoped two-dimensional electron gases (2DEG) and making very low resistivity contacts to these. We studied the evolution of mobility as a function of the depth of the 2DEG (from 310 to 30 nm). We extract quantitative information about the background impurity concentrations in GaAs and AlGaAs, the interface roughness, and the charge in the surface states. Surface charge sets an intrinsic limit to the mobility of very shallow 2DEGs. It is probably impossible to fabricate such shallow high-mobility 2DEGs using modulation doping due to the need to accommodate a spacer layer.
Show PACS
85.40.Ry Impurity doping, diffusion and ion implantation technology
81.05.Ea III-V semiconductors
61.72.uj III-V and II-VI semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.Fr Low-field transport and mobility; piezoresistance
68.35.Ct Interface structure and roughness

Band alignment of atomic layer deposited HfO2 on clean and N passivated germanium surfaces

Abdul K. Rumaiz, J. C. Woicik, G. A. Carini, D. P. Siddons, E. Cockayne, E. Huey, P. S. Lysaght, D. A. Fischer, and V. Genova

Appl. Phys. Lett. 97, 242108 (2010); http://dx.doi.org/10.1063/1.3524262 (3 pages) | Cited 3 times

Online Publication Date: 15 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Hard x-ray photoelectron spectroscopy has been used to study the band alignment between atomic layer deposited HfO2 on clean Ge (100) and nitrogen treated Ge (100) surfaces. The position of the valence-band maximum was determined by convolving theoretically calculated density of states from first-principles calculations and comparing with experimental valence-band data. Using Kraut’s method, the valence-band offsets were found to be 3.2±0.1 and 3.3±0.1 eV for the samples grown on clean and N passivated Ge, respectively. The oxide charge measured from capacitance-voltage measurements shows a significant increase between the two samples; however, the small change in the band offset between the two systems strongly indicates negligible contribution of the interface to the conduction/valence-band barrier and the band alignment of the heterojunctions.
Show PACS
77.55.dj For nonsilicon electronics (Ge, III-V, II-VI, organic electronics)
71.20.Ps Other inorganic compounds
79.60.Bm Clean metal, semiconductor, and insulator surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.aj Insulators
71.15.-m Methods of electronic structure calculations

End-group effects on negative differential resistance and rectifying performance of a polyyne-based molecular wire

M. Qiu, Z. H. Zhang, X. Q. Deng, and J. B. Pan

Appl. Phys. Lett. 97, 242109 (2010); http://dx.doi.org/10.1063/1.3526723 (3 pages) | Cited 1 time

Online Publication Date: 15 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Based on first-principles approach, the end-group effects on negative differential resistance (NDR) and rectifying performance of polyyne-based molecular wires are investigated. The NDR behaviors are observed when the polyyne is attached to asymmetric (–NO2 and –NH2) or symmetric (double –S) end groups, and rectifying performance emerges with the presence of asymmetric groups. The analysis on microscopic nature reveals the intrinsic origin of these phenomena. Our results show the possibility of a multifunctional molecular device design simultaneously with NDR and rectifying performances by using a technology of capping certain end groups to polyyne.
Show PACS
85.65.+h Molecular electronic devices

Kerr detection of acoustic spin transport in GaAs (110) quantum wells

A. Hernández-Mínguez, K. Biermann, S. Lazić, R. Hey, and P. V. Santos

Appl. Phys. Lett. 97, 242110 (2010); http://dx.doi.org/10.1063/1.3524218 (3 pages)

Online Publication Date: 16 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Time-resolved Kerr reflectometry (TRKR) is used to investigate the long-range transport of spins by surface acoustic waves in undoped GaAs (110) quantum wells. TRKR measurements under an applied magnetic field demonstrate the coherent precession of the optically generated electron spin during acoustic transport over several micrometers and yield information about the relaxation processes for moving spins.
Show PACS
73.63.Hs Quantum wells
72.25.Dc Spin polarized transport in semiconductors
72.50.+b Acoustoelectric effects
78.67.De Quantum wells
78.47.jg Time resolved reflection spectroscopy
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation

Passivation effects of fluorine and hydrogen at the SiC–SiO2 interface

Yingdi Liu, Michael R. Halfmoon, Christine A. Rittenhouse, and Sanwu Wang

Appl. Phys. Lett. 97, 242111 (2010); http://dx.doi.org/10.1063/1.3527943 (3 pages)

Online Publication Date: 17 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High concentrations of defects at the SiC–SiO2 interface significantly reduce the efficiency of the SiC-based microelectronics. Investigations of the defect passivation are thus of great importance. We report first-principles density-functional-theory calculations for the effects of fluorine and hydrogen in passivating the defects at the SiC–SiO2 interface. The calculations show that the isolated point defects involving excessive carbon atoms can be passivated by atomic fluorine and hydrogen, separately or combined. The results further suggest that molecular fluorine may be more effective for the passivation of the interface defects than molecular hydrogen and hydrogen fluoride.
Show PACS
81.65.Rv Passivation
82.45.Bb Corrosion and passivation
61.72.J- Point defects and defect clusters
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Effects of local structural defects on the electron transport in a carbon nanotube between Cu electrodes

Feng Gao, Jianmin Qu, and Matthew Yao

Appl. Phys. Lett. 97, 242112 (2010); http://dx.doi.org/10.1063/1.3527918 (3 pages) | Cited 2 times

Online Publication Date: 17 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using the first-principles approach with the Landauer formalism, we studied the effects of monovacancy and Stone–Wales defects on the electrical conductance of carbon nanotube (CNT) itself and its junction with copper electrodes. We found that the Stone–Wales defect has almost negligible impact on the electrical performance of the CNT(5,5) and its junction with copper at the Fermi level, while the monovacancy can reduce the electrical conductance of the CNT(5,5) significantly and that of the Cu/CNT(5,5)/Cu junction by more than 30%.
Show PACS
73.40.Sx Metal-semiconductor-metal structures
73.63.Fg Nanotubes
61.72.jd Vacancies
71.20.Tx Fullerenes and related materials; intercalation compounds
73.20.At Surface states, band structure, electron density of states
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Electron conduction in lateral granular oxide-metal tunnel junctions

Wenbin Fan, Jiwei Lu, and Stuart A. Wolf

Appl. Phys. Lett. 97, 242113 (2010); http://dx.doi.org/10.1063/1.3527965 (3 pages) | Cited 1 time

Online Publication Date: 17 December 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electron transport mechanisms in lateral tantalum granular oxide-metal tunnel junctions have been investigated at low temperatures that range from 30 to 300 K. Fowler–Nordheim tunneling was determined to be the dominant temperature-independent conducting mechanism at high field, while direct tunneling appeared in the low field regime. All the nonlinear current-voltage curves were well fitted by Simmons’ equation with barrier thickness, height, and tunneling area treated as variables. The temperature-dependent current transport can be described by variable range hopping and Coulomb blockade.
Show PACS
73.40.Gk Tunneling
73.23.Hk Coulomb blockade; single-electron tunneling
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close