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

30 May 2011

Volume 98, Issue 22, Articles (22xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 98, 223101 (2011); http://dx.doi.org/10.1063/1.3595266 (3 pages)

Takahiro Ohori, Yasuhide Ohno, Kenzo Maehashi, Koichi Inoue, Yutaka Hayashi, and Kazuhiko Matsumoto
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Multilayer graphene under vertical electric field

S. Bala Kumar and Jing Guo

Appl. Phys. Lett. 98, 222101 (2011); http://dx.doi.org/10.1063/1.3595335 (3 pages) | Cited 7 times

Online Publication Date: 31 May 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the effect of vertical electric field (E-field) on the electronic properties of multilayer graphene. We show that the effective mass, electron velocity, and density-of-state of a bilayer graphene are modified under the E-field. We also study the transformation of the band structure of multilayer graphenes. E-field induces finite (zero) band gap in the even (odd)-layer ABA-stacking graphene. On the other hand, finite band gap is induced in all ABC-stacking graphene. We also identify the optimum E-field to obtain the maximum band gap in the multilayer graphenes. Finally, we compare our results with the experimental results of a field-effect-transistor.
Show PACS
73.22.Pr Electronic structure of graphene
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
73.21.Ac Multilayers
61.48.Gh Structure of graphene

Effective passivation of Si surfaces by plasma deposited SiOx/a-SiNx:H stacks

G. Dingemans, M. M. Mandoc, S. Bordihn, M. C. M. van de Sanden, and W. M. M. Kessels

Appl. Phys. Lett. 98, 222102 (2011); http://dx.doi.org/10.1063/1.3595940 (3 pages) | Cited 7 times

Online Publication Date: 31 May 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Very low surface recombination velocities <6 and <11 cm/s were obtained for SiOx/a-SiNx:H stacks synthesized by plasma-enhanced chemical vapor deposition on low resistivity n- and p-type c-Si, respectively. The stacks induced a constant effective lifetime under low illumination, comparable to Al2O3 on p-type Si. Compared to single layer a-SiNx:H, a lower positive fixed charge density was revealed by second-harmonic generation measurements, while field-effect passivation was absent for a reference stack comprising thermally grown SiO2. The results indicate that hydrogenation of interface states played a key role in the passivation and remained effective up to annealing temperatures >800 °C.
Show PACS
81.65.Rv Passivation
61.43.-j Disordered solids
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Two-dimensional electron gas transport anisotropy in N-polar GaN/AlGaN heterostructures

G. A. Umana-Membreno, T. B. Fehlberg, S. Kolluri, D. F. Brown, S. Keller, U. K. Mishra, B. D. Nener, L. Faraone, and G. Parish

Appl. Phys. Lett. 98, 222103 (2011); http://dx.doi.org/10.1063/1.3595341 (3 pages) | Cited 2 times

Online Publication Date: 1 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetic-field dependent Hall-effect measurements and mobility spectrum analysis were employed to study anisotropic transport in N-polar GaN/Al0.3Ga0.7N heterostructures grown on vicinal sapphire substrates. The significant anisotropy in the mobility in the parallel and perpendicular directions to the miscut direction was accompanied by a slight anisotropy in charge density. A single electron species was found in the direction parallel to the steps resulting from growth on the vicinal substrates; while in the perpendicular direction two distinct electrons peaks were evident at T ≤ 150 K. The lower average mobility in the perpendicular direction is attributed to interface roughness scattering.
Show PACS
81.05.Ea III-V semiconductors
68.35.Ct Interface structure and roughness
72.20.Fr Low-field transport and mobility; piezoresistance
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Accuracy evaluation of single-electron shuttle transfer in Si nanowire metal-oxide-semiconductor field-effect transistors

Gento Yamahata, Katsuhiko Nishiguchi, and Akira Fujiwara

Appl. Phys. Lett. 98, 222104 (2011); http://dx.doi.org/10.1063/1.3595683 (3 pages) | Cited 1 time

Online Publication Date: 2 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on evaluation of transfer accuracy in a single-electron turnstile using silicon nanowire metal-oxide-semiconductor field-effect transistors at 17 K. Single-electron shuttle transfer and single-shot detection of a single electron are used to detect errors of the transfer. Errors for the transfer through an electrostatically formed island are ascribed to thermal processes. We also observed single-electron transfer mediated by a trap level, which exhibits a wide current plateau and a low error rate.
Show PACS
81.05.Cy Elemental semiconductors
85.30.Tv Field effect devices
81.07.Gf Nanowires

Effect of SiC wafer miscut angle on the morphology and Hall mobility of epitaxially grown graphene

Christos Dimitrakopoulos, Alfred Grill, Timothy J. McArdle, Zihong Liu, Robert Wisnieff, and Dimitri A. Antoniadis

Appl. Phys. Lett. 98, 222105 (2011); http://dx.doi.org/10.1063/1.3595945 (3 pages) | Cited 3 times

Online Publication Date: 2 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show that the surface morphology and electrical properties of graphene grown on SiC(0001) wafers depend strongly on miscut angle, even for nominally “on-axis” wafers. Graphene grown on pit-free surfaces with narrow terraces (miscut above 0.28°) shows substantially lower Hall mobility than graphene on surfaces with miscut angles below 0.1° that have wider terraces with some pits. The effect of pits on mobility is not detrimental if flat, pit-free areas with dimensions larger than the carrier mean free path remain between pits. Using these results, we optimized the growth process, achieving room-temperature mobility up to 3015 cm2/V s at N = 2.0×1012 cm−2.
Show PACS
72.80.Vp Electronic transport in graphene
68.47.-b Solid-gas/vacuum interfaces: types of surfaces
72.20.Ee Mobility edges; hopping transport
72.20.My Galvanomagnetic and other magnetotransport effects
61.48.Gh Structure of graphene

An observation of charge trapping phenomena in GaN/AlGaN/Gd2O3/Ni–Au structure

Liann Be Chang, Atanu Das, Ray Ming Lin, Siddheswar Maikap, Ming Jer Jeng, and Shu Tsun Chou

Appl. Phys. Lett. 98, 222106 (2011); http://dx.doi.org/10.1063/1.3596382 (3 pages) | Cited 3 times

Online Publication Date: 2 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Charge trapping, especially electron trapping phenomena in GaN/AlGaN/Gd2O3/Ni–Au metal-oxide-semiconductor structure have been investigated. Owing to crystallization of Gd2O3 film after annealing at 900 °C in ambient air for 30 s, a significant memory window of 1.6 V is observed under 5 V@100 ms programming pulse compared with that of as-deposited sample. The fabricated structure exhibits no erase phenomena under large negative bias of −20 V. Only time dependent natural charge loss is occurred. Even so, 0.9 V of memory window is still remained after 21 h of retention. Good endurance of 103 cycles with 2.0 V memory window is also obtained.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.Cc Kinetics of defect formation and annealing
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Observation of the memory steps in graphene at elevated temperatures

Sergey L. Rumyantsev, Guanxiong Liu, Michael S. Shur, and Alexander A. Balandin

Appl. Phys. Lett. 98, 222107 (2011); http://dx.doi.org/10.1063/1.3596441 (3 pages) | Cited 2 times

Online Publication Date: 2 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We found that the current-voltage characteristics of graphene transistors exhibit an intriguing feature—an abrupt change in the current near zero gate bias at temperatures above 500 K. The strength of this effect, which we refer to as the memory step by analogy with the memory dips—known phenomenon in electron glasses, depends on the rate of the gate voltage sweep. The slower the sweep, the more pronounced is the step in the current. Despite differences in examined graphene transistors, the memory step always appears at Vg ≈ 0 V. The observed memory steps are likely related to the slow relaxation processes in graphene. This new phenomenon in graphene can be used for applications in sensors and switches.
Show PACS
85.35.Gv Single electron devices
85.65.+h Molecular electronic devices

Electron hopping interactions in amorphous ZnO films probed by x-ray absorption near edge structure analysis

Deok-Yong Cho, Jeong Hwan Kim, and Cheol Seong Hwang

Appl. Phys. Lett. 98, 222108 (2011); http://dx.doi.org/10.1063/1.3596701 (3 pages)

Online Publication Date: 3 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The x-ray absorption near edge structures of amorphous ZnO (a-ZnO) films were examined. The near-edge structure, which reflects the virtual electron hopping interactions in the photoabsorption final states, increased in intensity compared to crystalline ZnO. Theoretical path-by-path analyses revealed that this reflects the extinction of the multiple hopping processes found in paths such as Zn→O→O′→Zn or Zn→O→Zn′→Zn while the Zn–(O or Zn) hopping interactions remain. This suggests that the structural disorders in a-ZnO can induce the localization of the conduction band through the limited hopping interactions.
Show PACS
73.61.Ga II-VI semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Hf II-VI semiconductors
78.70.Dm X-ray absorption spectra

Effects of substrate orientation on the structural and electronic properties of epitaxial graphene on SiC(0001)

Joshua A. Robinson, Kathleen A. Trumbull, Michael LaBella, III, Randall Cavalero, Matthew J. Hollander, Michael Zhu, Maxwell T. Wetherington, Mark Fanton, and David W. Snyder

Appl. Phys. Lett. 98, 222109 (2011); http://dx.doi.org/10.1063/1.3597356 (3 pages) | Cited 4 times

Online Publication Date: 3 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate graphene transport and structural properties as a function of silicon carbide (SiC) wafer orientation. Terrace step edge density is found to increase with wafer misorientation from SiC(0001). This results in a monotonic increase in average graphene thickness, as well as a 30% increase in carrier density and 40% decrease in mobility up to 0.45° miscut toward (1math00). Beyond 0.45°, average thickness and carrier density continues to increase; however, carrier mobility is similar to low-miscut angles, suggesting that the interaction between graphene and SiC(0001) may be fundamentally different that of graphene/SiC(1math0n).
Show PACS
72.20.Fr Low-field transport and mobility; piezoresistance
73.61.Wp Fullerenes and related materials
61.48.Gh Structure of graphene
73.22.Pr Electronic structure of graphene

Rare earth chalcogenide Ce3Te4 as high efficiency high temperature thermoelectric material

Xiaochun Wang, Ronggui Yang, Yong Zhang, Peihong Zhang, and Yu Xue

Appl. Phys. Lett. 98, 222110 (2011); http://dx.doi.org/10.1063/1.3597409 (3 pages) | Cited 1 time

Online Publication Date: 3 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic band structures of Ce3Te4 have been studied using the first-principles density-functional theory calculations. It is found that the density of states of Ce3Te4 has a very high delta-shaped peak appearing 0.21 eV above the Fermi level, which mainly comes from the f orbital electrons of the rare-earth element Ce. Using the simple theory proposed by Mahan and Sofo, [Proc. Natl. Acad. Sci. U.S.A. 93, 7436 (1996)] , we obtain an ideal value of zT = 13.5 for Ce3Te4 at T = 1200 K, suggesting that the rare-earth chalcogenide Ce3Te4 could be a promising high efficiency high temperature thermoelectric material.
Show PACS
72.20.Pa Thermoelectric and thermomagnetic effects
73.20.At Surface states, band structure, electron density of states
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.20.Nr Semiconductor compounds

Analysis of surface morphology at leakage current sources of 4H–SiC Schottky barrier diodes

Takashi Katsuno, Yukihiko Watanabe, Hirokazu Fujiwara, Masaki Konishi, Hideki Naruoka, Jun Morimoto, Tomoo Morino, and Takeshi Endo

Appl. Phys. Lett. 98, 222111 (2011); http://dx.doi.org/10.1063/1.3597413 (3 pages) | Cited 2 times

Online Publication Date: 3 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface morphologies of leakage current sources of 4H–SiC Schottky barrier diode were analyzed using atomic force microscopy (AFM). Nanosized circular cone shaped pits (nanopits) were observed at the leakage current sources. Leakage currents were generated due to the concentration of electric fields at the nanopits during measurements of the reverse bias characteristics. The positions of the nanopits correspond to the positions of threading dislocations (TDs), which were identified from molten potassium hydroxide (KOH) etching. The most important factor of leakage current generation was determined to be the surface morphology of the TDs rather than the presence of TDs.
Show PACS
85.30.Kk Junction diodes

Replacement of oxide glass with metallic glass for Ag screen printing metallization on Si emitter

Se Yun Kim, Sang Soo Jee, Ka Ram Lim, Won Tae Kim, Do Hyang Kim, Eun-Sung Lee, Young Hwan Kim, Sang Mock Lee, Jun Ho Lee, and Jürgen Eckert

Appl. Phys. Lett. 98, 222112 (2011); http://dx.doi.org/10.1063/1.3596469 (3 pages) | Cited 6 times

Online Publication Date: 3 June 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cu–Zr-based metallic glass (MG) has been applied as a binding agent of Ag paste for front contact formation in Si solar cell by screen printing process. Use of electroconductive MG binder significantly improves the quality of the contact by the formation of highly dense 10–50 nm size Ag crystallites and the noncorrugation of the emitter surface with a very shallow Ag crystallite penetration depth of 10–30 nm. Nanoscale Ag crystallites form on the emitter surface by local Si–Cu–Ag eutectic melting, leading to the formation of pyramidal pits on the Si emitter surface, followed by precipitation of Ag crystallites during cooling.
Show PACS
88.40.jj Silicon solar cells
85.40.Ls Metallization, contacts, interconnects; device isolation
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close