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

1 Jun 2009

Volume 94, Issue 22, Articles (22xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 221101 (2009); http://dx.doi.org/10.1063/1.3143652 (3 pages)

Gangyi Xu, Virginie Moreau, Yannick Chassagneux, Adel Bousseksou, Raffaele Colombelli, G. Patriarche, G. Beaudoin, and I. Sagnes
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Modeling single-particle energy levels and resonance currents in a coherent electronic quantum dot mixer

C. Payette, B. Partoens, G. Yu, J. A. Gupta, D. G. Austing, S. V. Nair, S. Amaha, and S. Tarucha

Appl. Phys. Lett. 94, 222101 (2009); http://dx.doi.org/10.1063/1.3147196 (3 pages) | Cited 2 times

Online Publication Date: 1 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present model calculations based on a coherent tunneling picture, which reproduce well both the single-particle energy level position and the resonant current strength at two typical anticrossings, one involving two levels and the other three levels in a coherent mixer composed of two weakly coupled vertical quantum dots. An essential ingredient is the inclusion of higher degree terms to account for deviations from an ideal elliptical parabolic confining potential in realistic dots. We also calculate density plots of the mixed states for the modified potential.
Show PACS
73.21.La Quantum dots
73.23.Hk Coulomb blockade; single-electron tunneling
73.63.Kv Quantum dots
73.40.Gk Tunneling

Enhancement of responsivity in solar-blind β-Ga2O3 photodiodes with a Au Schottky contact fabricated on single crystal substrates by annealing

Rikiya Suzuki, Shinji Nakagomi, Yoshihiro Kokubun, Naoki Arai, and Shigeo Ohira

Appl. Phys. Lett. 94, 222102 (2009); http://dx.doi.org/10.1063/1.3147197 (3 pages) | Cited 8 times

Online Publication Date: 1 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We fabricated β-Ga2O3 photodiodes with a Au Schottky contact on a single crystal substrate and investigated the effect of postannealing on the electrical and optical properties of the photodiodes. The ideality factor improved to near unity by annealing at temperatures above 200 °C; however, the reverse leakage current remained nearly unchanged. The responsivity in the wavelength region below 260 nm was enhanced dramatically by a factor of more than 102 after annealing at 400 °C resulting in maximum responsivity of 103 A/W, accompanied with a contrast ratio of about six orders of magnitude between the responsivities at 240 and 350 nm.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
73.30.+y Surface double layers, Schottky barriers, and work functions

Controlling the conductance and noise of driven carbon-based Fabry–Pérot devices

Luis E. F. Foa Torres and Gianaurelio Cuniberti

Appl. Phys. Lett. 94, 222103 (2009); http://dx.doi.org/10.1063/1.3147865 (3 pages) | Cited 11 times

Online Publication Date: 1 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on ac transport through carbon nanotube Fabry–Pérot devices. We show that tuning the intensity of the ac gating induces an alternation of suppression and partial revival of the conductance interference pattern. For frequencies matching integer multiples of the level spacing of the system Δ, the conductance remains irresponsive to the external field. In contrast, the noise in the low bias voltage limit behaves as in the static case only when the frequency matches an even multiple of the level spacing, thereby highlighting its phase sensitivity in a manifestation of the wagon-wheel effect in the quantum domain.
Show PACS
85.35.Kt Nanotube devices

Tailoring the hole concentration in superlattices based on nitride alloys

Qing-Hong Zheng, Yi-An Yin, Li-Hong Zhu, Jin Huang, Xiao-Ying Li, and Bao-Lin Liu

Appl. Phys. Lett. 94, 222104 (2009); http://dx.doi.org/10.1063/1.3148244 (3 pages) | Cited 1 time

Online Publication Date: 1 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By introducing Mg-doped InGaN/AlGaN strained-layer superlattice (SL) as p-type layer, the performance of p-type Ohmic contact is improved as compared with AlGaN/GaN and InGaN/GaN SLs. InGaN/AlGaN SL yields higher hole concentration due to larger oscillation of the valence band edge and smaller activation energy. The calculated average hole concentration in InGaN/AlGaN SL shows a twofold increase compared to that in AlGaN/GaN SL at the same Mg-doped level. The measured sheet hole density for ten periods of InGaN/AlGaN SL is as high as 4.4×1014 cm−2. Finally, Ni/Au contacts on Mg-doped InGaN/AlGaN SL with specific contact resistance of 7.3×10−5 Ω cm2 are realized.
Show PACS
73.63.-b Electronic transport in nanoscale materials and structures
72.20.-i Conductivity phenomena in semiconductors and insulators
73.40.Ns Metal-nonmetal contacts
73.40.Cg Contact resistance, contact potential

Metal organic chemical vapor deposition of crack-free GaN-based light emitting diodes on Si (111) using a thin Al2O3 interlayer

William E. Fenwick, Andrew Melton, Tianming Xu, Nola Li, Christopher Summers, Muhammad Jamil, and Ian T. Ferguson

Appl. Phys. Lett. 94, 222105 (2009); http://dx.doi.org/10.1063/1.3148328 (3 pages) | Cited 3 times

Online Publication Date: 1 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Crack-free GaN light emitting diodes (LEDs) have been grown by metal organic chemical vapor deposition on Si(111) substrates using an atomic layer deposition-grown Al2O3 interlayer. Devices on Si show a longer emission wavelength compared to those on sapphire. This is attributed to tensile strain in the layers on Si, which may increase indium incorporation. Internal quantum efficiency is similar on both substrates. Luminescence intensity versus current density measurements show higher efficiency for the LEDs on Si relative to sapphire at high drive currents. These results show comparable performance characteristics for GaN-based devices on Si and sapphire substrates.
Show PACS
85.60.Jb Light-emitting devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Terahertz generation in GaN diodes operating in pulsed regime limited by self-heating

E. A. Barry, V. N. Sokolov, K. W. Kim, and R. J. Trew

Appl. Phys. Lett. 94, 222106 (2009); http://dx.doi.org/10.1063/1.3147217 (3 pages) | Cited 2 times

Online Publication Date: 2 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The conditions for pulsed regime operation of terahertz power generation in vertical nanoscale GaN-based diodes are investigated via self-consistent simulation of the high-field electron transport in the active channel and thermal transport in the entire device structure. The combined electrothermal model allows for a detailed analysis of the dynamical local distributions of the electric field, drift-velocity, and lattice temperature. We show that stable generation is achievable with a self-heating limited output power of 2.25 W at an operation frequency of 0.71 THz for a pulse width of 3 ns with a few tens of nanosecond duty cycle.
Show PACS
85.30.Kk Junction diodes

Transport through graphene double dots

F. Molitor, S. Dröscher, J. Güttinger, A. Jacobsen, C. Stampfer, T. Ihn, and K. Ensslin

Appl. Phys. Lett. 94, 222107 (2009); http://dx.doi.org/10.1063/1.3148367 (3 pages) | Cited 29 times

Online Publication Date: 2 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present Coulomb blockade measurements in a graphene double dot system. The coupling of the dots to the leads and between the dots can be tuned by graphene in-plane gates. The coupling is a nonmonotonic function of the gate voltage. Using a purely capacitive model, we extract all relevant energy scales of the double dot system.
Show PACS
73.63.Kv Quantum dots
73.23.Hk Coulomb blockade; single-electron tunneling

Reduction of native oxides on GaAs during atomic layer growth of Al2O3

Hang Dong Lee, Tian Feng, Lei Yu, Daniel Mastrogiovanni, Alan Wan, Torgny Gustafsson, and Eric Garfunkel

Appl. Phys. Lett. 94, 222108 (2009); http://dx.doi.org/10.1063/1.3148723 (3 pages) | Cited 16 times

Online Publication Date: 2 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The reduction of surface “native” oxides from GaAs substrates following reactions with trimethylaluminum (TMA) precursor is studied using medium energy ion scattering spectroscopy (MEIS) and x-ray photoelectron spectroscopy (XPS). MEIS measurements after one single TMA pulse show that ∼ 65% of the native oxide is reduced, confirmed by XPS measurement, and a 5 Å thick oxygen-rich aluminum oxide layer is formed. This reduction occurs upon TMA exposure to as-received GaAs wafers.
Show PACS
82.30.-b Specific chemical reactions; reaction mechanisms
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Electrical detection of spin precession in single layer graphene spin valves with transparent contacts

Wei Han, K. Pi, W. Bao, K. M. McCreary, Yan Li, W. H. Wang, C. N. Lau, and R. K. Kawakami

Appl. Phys. Lett. 94, 222109 (2009); http://dx.doi.org/10.1063/1.3147203 (3 pages) | Cited 25 times

Online Publication Date: 3 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spin accumulation and spin precession in single layer graphene are studied by nonlocal spin valve measurements at room temperature. The dependence of the nonlocal magnetoresistance on electrode spacing is investigated and the results indicate a spin diffusion length of ∼ 1.6 μm and a spin injection/detection efficiency of 0.013. Electrical detection of the spin precession confirms that the nonlocal signal originates from spin injection and transport. Fitting of the Hanle spin precession data yields a spin relaxation time of ∼ 84 ps and a spin diffusion length of ∼ 1.5 μm, which is consistent with the value obtained through the spacing dependence.
Show PACS
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
72.25.Hg Electrical injection of spin polarized carriers
72.25.Rb Spin relaxation and scattering
72.25.Mk Spin transport through interfaces
75.47.Pq Other materials
75.30.Ds Spin waves
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)

Low temperature charge carrier hopping transport mechanism in vanadium oxide thin films grown using pulsed dc sputtering

S. S. N. Bharadwaja, C. Venkatasubramanian, N. Fieldhouse, S. Ashok, M. W. Horn, and T. N. Jackson

Appl. Phys. Lett. 94, 222110 (2009); http://dx.doi.org/10.1063/1.3139864 (3 pages) | Cited 9 times

Online Publication Date: 4 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Low temperature charge transport in vanadium oxide (VOx) thin films processed using pulsed dc sputtering is investigated to understand the correlation between the processing conditions and electrical properties. It is identified that the temperature dependent resistivity ρ(T) of the VOx thin films is dominated by a Efros–Shklovskii variable range hopping mechanism [ Efros and Shklovskii, J. Phys. C 8, L49 (1975) ]. A detailed analysis in terms of charge hopping parameters in the low temperature regime is used to correlate film properties with the pulsed dc sputtering conditions.
Show PACS
73.50.Dn Low-field transport and mobility; piezoresistance
81.15.Cd Deposition by sputtering
73.61.Ng Insulators
68.55.aj Insulators

Thickness dependence of the mobility at the LaAlO3/SrTiO3 interface

C. Bell, S. Harashima, Y. Hikita, and H. Y. Hwang

Appl. Phys. Lett. 94, 222111 (2009); http://dx.doi.org/10.1063/1.3149695 (3 pages) | Cited 30 times

Online Publication Date: 5 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic transport properties of a series of LaAlO3/SrTiO3 interfaces were investigated, and a systematic thickness dependence of the sheet resistance and magnetoresistance was found for constant growth conditions. This trend occurs above the critical thickness of four unit cells, below which the LaAlO3/SrTiO3 interface is not conducting. A dramatic decrease in mobility of the electron gas of nearly two orders of magnitude was observed with increasing LaAlO3 thickness from 5 to 25 unit cells.
Show PACS
72.20.My Galvanomagnetic and other magnetotransport effects
72.20.Fr Low-field transport and mobility; piezoresistance
73.40.-c Electronic transport in interface structures
68.35.Ct Interface structure and roughness

Comparative study of electrical instabilities in top-gate InGaZnO thin film transistors with Al2O3 and Al2O3/SiNx gate dielectrics

Jeong-Min Lee, In-Tak Cho, Jong-Ho Lee, Woo-Seok Cheong, Chi-Sun Hwang, and Hyuck-In Kwon

Appl. Phys. Lett. 94, 222112 (2009); http://dx.doi.org/10.1063/1.3151865 (3 pages) | Cited 22 times

Online Publication Date: 5 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A comparative study was made of the performance and electrical instabilities in amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors with Al2O3 and Al2O3/SiNx gate dielectrics. Steeper subthreshold slope is observed in Al2O3 devices, which shows that the density of trap states at the interface of a-IGZO/Al2O3 is lower than that of a-IGZO/SiNx. Under high bias-stresses, a larger degradation is observed in Al2O3/SiNx devices. The device degradation for both devices are mainly attributed to the charge trapping phenomenon, but the different time dependence of threshold voltage shift shows that trapped electrons are more easily redistributed inside the Al2O3 dielectrics.
Show PACS
85.30.Tv Field effect devices

Characterization of near-infrared n-type β-FeSi2/p-type Si heterojunction photodiodes at room temperature

Mahmoud Shaban, Keita Nomoto, Shota Izumi, and Tsuyoshi Yoshitake

Appl. Phys. Lett. 94, 222113 (2009); http://dx.doi.org/10.1063/1.3151915 (3 pages) | Cited 17 times

Online Publication Date: 5 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
n-type β-FeSi2/p-type Si heterojunctions were fabricated from β-FeSi2 films epitaxially grown on Si(111) by facing-target direct-current sputtering. Sharp film-substrate interfaces were confirmed by scanning electron microscopy. The current-voltage and photoresponse characteristics were measured at room temperature. They exhibited good rectifying properties and a change of approximately one order of magnitude in the current at a bias voltage of −1 V under illumination by a 6 mW, 1.31 μm laser. The estimated detectivity was 1.5×109 cm √Hz W at 1.31 μm. The results suggest that the β-FeSi2/Si heterojunctions can be used as near-infrared photodetectors that are compatible with silicon integrated circuits.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.15.Cd Deposition by sputtering
68.55.ag Semiconductors
85.60.Gz Photodetectors (including infrared and CCD detectors)
73.40.Ei Rectification

Determination of wurtzite InN/cubic In2O3 heterojunction band offset by x-ray photoelectron spectroscopy

H. P. Song, A. L. Yang, H. Y. Wei, Y. Guo, B. Zhang, G. L. Zheng, S. Y. Yang, X. L. Liu, Q. S. Zhu, Z. G. Wang, T. Y. Yang, and H. H. Wang

Appl. Phys. Lett. 94, 222114 (2009); http://dx.doi.org/10.1063/1.3151956 (3 pages) | Cited 12 times

Online Publication Date: 5 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In2O3 is a promising partner of InN to form InN/In2O3 heterosystems. The valence band offset (VBO) of wurtzite InN/cubic In2O3 heterojunction is determined by x-ray photoemission spectroscopy. The valence band of In2O3 is found to be 1.47±0.11 eV below that of InN, and a type-I heterojunction with a conduction band offset (CBO) of 0.49–0.99 eV is found. The accurate determination of the VBO and CBO is important for use of InN/In2O3 based electronic devices.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
79.60.Jv Interfaces; heterostructures; nanostructures
81.05.Ea III-V semiconductors

Change in the resistivity of Ge-doped Sb phase change thin films grown by chemical vapor deposition according to their microstructures

Jin-Hyock Kim, Keun Lee, Su-Jin Chae, Il-Keoun Han, Jae-Sung Roh, Sung-Ki Park, Byung Joon Choi, Cheol Seong Hwang, Eunae Cho, and Seungwu Han

Appl. Phys. Lett. 94, 222115 (2009); http://dx.doi.org/10.1063/1.3151959 (3 pages) | Cited 1 time

Online Publication Date: 5 June 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This study examined the effects of the composition and microstructure on the electric resistivity of Ge-doped Sb phase change thin films grown by cyclic plasma enhanced chemical vapor deposition. Ge and Sb layers were deposited sequentially to form either a GexSby mixture or Ge/Sb nanolaminated films. While the resistivity of the nanolaminated films was higher, the GexSby mixture showed a lower resistivity than the pure Sb film. This can be explained by the increase in carrier density of the alloy, as confirmed by first-principles calculations. An abrupt change in resistance accompanying a phase change was observed at ∼ 210 °C.
Show PACS
73.61.At Metal and metallic alloys
71.15.-m Methods of electronic structure calculations
81.05.Bx Metals, semimetals, and alloys
81.07.Bc Nanocrystalline materials
71.20.Be Transition metals and alloys
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close