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

19 Mar 2012

Volume 100, Issue 12, Articles (12xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 121101 (2012); http://dx.doi.org/10.1063/1.3693413 (4 pages)

Jolly Xavier, Raktim Dasgupta, Sunita Ahlawat, Joby Joseph, and Pradeep Kumar Gupta
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Ti10Sb60Te30 for phase change memory with high-temperature data retention and rapid crystallization speed

Min Zhu, Liangcai Wu, Zhitang Song, Feng Rao, Daolin Cai, Cheng Peng, Xilin Zhou, Kun Ren, Sannian Song, Bo liu, and Songlin Feng

Appl. Phys. Lett. 100, 122101 (2012); http://dx.doi.org/10.1063/1.3695036 (4 pages) | Cited 4 times

Online Publication Date: 19 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
With a high crystallization temperature of 211 °C, Ti10Sb60Te30 phase change material exhibits a data retention of 10-yr at 137 °C, which is much better than that of usual Ge2Sb2Te5. No other phase is formed in Ti10Sb60Te30 film except hexagonal Sb2Te phase. For Ti10Sb60Te30-based phase change memory cell, as short as 6 ns electric pulse can fulfill the Set operation, demonstrating an extremely rapid crystallization speed of Ti10Sb60Te30. The programming cycles can reach 2.2 × 104 with very short Set/Reset pulses of 100 ns/50 ns.
Show PACS
84.30.Sk Pulse and digital circuits

A switch for epitaxial graphene electronics: Utilizing the silicon carbide substrate as transistor channel

F. Krach, S. Hertel, D. Waldmann, J. Jobst, M. Krieger, S. Reshanov, A. Schöner, and H. B. Weber

Appl. Phys. Lett. 100, 122102 (2012); http://dx.doi.org/10.1063/1.3695157 (3 pages) | Cited 2 times

Online Publication Date: 19 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Due to the lack of graphene transistors with large on/off ratio, we propose a concept employing both epitaxial graphene and its underlying substrate silicon carbide (SiC) as electronic materials. We demonstrate a simple, robust, and scalable transistor, in which graphene serves as electrodes and SiC as a semiconducting channel. The common interface has to be chosen such that it provides favorable charge injection. The insulator and gate functionality is realized by an ionic liquid gate for convenience but could be taken over by a solid gate stack. On/off ratios exceeding 44000 at room temperature are found.
Show PACS
85.30.Tv Field effect devices

Generalized conductivity model for polar semiconductors at terahertz frequencies

J. Lloyd-Hughes

Appl. Phys. Lett. 100, 122103 (2012); http://dx.doi.org/10.1063/1.3695161 (3 pages) | Cited 4 times

Online Publication Date: 19 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A theoretical framework is presented that calculates the conductivity of polar semiconductors at terahertz frequencies without resorting to phenomenological fit parameters, using an expression derived from the Boltzmann transport equation. The time-dependent photoconductivity of InAs and the temperature dependent conductivity of n-doped GaAs are found experimentally by terahertz time-domain spectroscopy. The observed deviation from the Drude-Lorentz conductivity in these model systems is accounted for by this approach, which calculates the energy-dependent electron scattering time.
Show PACS
72.20.Fr Low-field transport and mobility; piezoresistance
72.80.Ey III-V and II-VI semiconductors
72.40.+w Photoconduction and photovoltaic effects
78.70.Gq Microwave and radio-frequency interactions

High Si and Ge n-type doping of GaN doping - Limits and impact on stress

S. Fritze, A. Dadgar, H. Witte, M. Bügler, A. Rohrbeck, J. Bläsing, A. Hoffmann, and A. Krost

Appl. Phys. Lett. 100, 122104 (2012); http://dx.doi.org/10.1063/1.3695172 (4 pages) | Cited 7 times

Online Publication Date: 19 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on GaN n-type doping using silane, germane, and isobutylgermane as Si and Ge dopants, respectively. A significant increase in tensile stress during growth is observed for Si doped samples while this is not the case for Ge doping. In addition, Ge can be doped up to 2.9 × 1020 cm−3, while Si doping leads to 3-D growth already at concentrations around 1.9 × 1019 cm−3. The free carrier concentration was determined by Hall-effect measurements, crystal quality, and structural properties by x-ray diffraction measurements. Additionally, secondary ion mass spectroscopy and Raman measurements were performed demonstrating the high material quality of Ge doped samples.
Show PACS
61.72.uj III-V and II-VI semiconductors
72.80.Ey III-V and II-VI semiconductors
78.30.Fs III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
72.20.Fr Low-field transport and mobility; piezoresistance

Low energy electron beam induced vacancy activation in GaN

H. Nykänen, S. Suihkonen, L. Kilanski, M. Sopanen, and F. Tuomisto

Appl. Phys. Lett. 100, 122105 (2012); http://dx.doi.org/10.1063/1.3696047 (3 pages) | Cited 5 times

Online Publication Date: 21 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Experimental evidence on low energy electron beam induced point defect activation in GaN grown by metal-organic vapor phase epitaxy (MOVPE) is presented. The GaN samples are irradiated with a 5–20 keV electron beam of a scanning electron microscope and investigated by photoluminescence and positron annihilation spectroscopy measurements. The degradation of the band-to-band luminescence of the irradiated GaN films is associated with the activation of point defects. The activated defects were identified as in-grown Ga-vacancies. We propose that MOVPE-GaN contains a significant concentration of passive VGa-Hn complexes that can be activated by H removal during low energy electron irradiation.
Show PACS
61.80.Fe Electron and positron radiation effects
78.70.Bj Positron annihilation
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

SiN passivation layer effects on un-gated two-dimensional electron gas density in AlGaN/AlN/GaN field-effect transistors

A. Asgari and L. Faraone

Appl. Phys. Lett. 100, 122106 (2012); http://dx.doi.org/10.1063/1.3696641 (3 pages) | Cited 2 times

Online Publication Date: 21 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper, we present a study of SiN passivation layer effects on the two-dimensional electron gas (2DEG) sheet density in unintentionally doped AlGaN/AlN/GaN heterostructures, using a polarization model based on interface charges and a fully numerical calculation. The analysis of our results clearly indicates that there are at least two occupied sub-bands in the 2DEG for passivated AlGaN/AlN/GaN heterostructures, and with increasing passivation layer thickness and AlN interlayer thickness the 2DEG density increases. The comparison of our calculated results with published experimental data is shown to be in a very good agreement.
Show PACS
85.30.Tv Field effect devices
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Determination of exciton diffusion lengths in isotopically engineered diamond junctions

J. Barjon, F. Jomard, A. Tallaire, J. Achard, and F. Silva

Appl. Phys. Lett. 100, 122107 (2012); http://dx.doi.org/10.1063/1.3689783 (4 pages) | Cited 1 time

Online Publication Date: 21 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A direct observation of exciton diffusion in isotopically engineered 12C/13C diamond junctions is presented. Excitons generated under a focused electron beam in the higher-energy bandgap 13C diamond diffuse and part of them are collected in the lower-energy bandgap 12C diamond, where they recombine. By using cathodoluminescence spectroscopy on samples in cross-section, the recombination intensity is followed as a function of the electron-beam distance to the 12C/13C interface. Exciton diffusion lengths in 13C diamond up to 7.9 µm at 10 K are deduced.
Show PACS
71.35.-y Excitons and related phenomena
78.60.Hk Cathodoluminescence, ionoluminescence
66.30.-h Diffusion in solids

Self-adaptive electronic contact between graphene and semiconductors

Haijian Zhong, Zhenghui Liu, Gengzhao Xu, Yingmin Fan, Jianfeng Wang, Xuemin Zhang, Liwei Liu, Ke Xu, and Hui Yang

Appl. Phys. Lett. 100, 122108 (2012); http://dx.doi.org/10.1063/1.3696671 (4 pages) | Cited 4 times

Online Publication Date: 22 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Understanding the contact properties of graphene on semiconductors is crucial to improving the performance of graphene optoelectronic devices. Here, we show that when graphene is in contact with a semiconductor, the charge carrier transport into graphene leads to a self-adaptive shift of the Fermi level, which tends to lower the barrier heights of the graphene contact to both n- and p-type semiconductors. A theoretical model is presented to describe the charge carrier transport mechanism and to quantitatively estimate the barrier heights. These results can benefit recent topical approaches for graphene integration in various semiconductor devices.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
81.05.ue Graphene

Evaluation of freestanding boron-doped diamond grown by chemical vapour deposition as substrates for vertical power electronic devices

R. Issaoui, J. Achard, A. Tallaire, F. Silva, A. Gicquel, R. Bisaro, B. Servet, G. Garry, and J. Barjon

Appl. Phys. Lett. 100, 122109 (2012); http://dx.doi.org/10.1063/1.3697568 (4 pages) | Cited 1 time

Online Publication Date: 22 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study, 4 × 4 mm2 freestanding boron-doped diamond single crystals with thickness up to 260 μm have been fabricated by plasma assisted chemical vapour deposition. The boron concentrations measured by secondary ion mass spectroscopy were 1018 to 1020 cm−3 which is in a good agreement with the values calculated from Fourier transform infrared spectroscopy analysis, thus indicating that almost all incorporated boron is electrically active. The dependence of lattice parameters and crystal mosaicity on boron concentrations have also been extracted from high resolution x-ray diffraction experiments on (004) planes. The widths of x-ray rocking curves have globally shown the high quality of the material despite a substantial broadening of the peak, indicating a decrease of structural quality with increasing boron doping levels. Finally, the suitability of these crystals for the development of vertical power electronic devices has been confirmed by four-point probe measurements from which electrical resistivities as low as 0.26 Ω cm have been obtained.
Show PACS
81.10.Bk Growth from vapor
85.30.-z Semiconductor devices
61.72.U- Doping and impurity implantation
52.77.Dq Plasma-based ion implantation and deposition
78.30.Hv Other nonmetallic inorganics
61.66.-f Structure of specific crystalline solids

Design of three-well indirect pumping terahertz quantum cascade lasers for high optical gain based on nonequilibrium Green’s function analysis

Tao Liu, Tillmann Kubis, Qi Jie Wang, and Gerhard Klimeck

Appl. Phys. Lett. 100, 122110 (2012); http://dx.doi.org/10.1063/1.3697674 (4 pages) | Cited 3 times

Online Publication Date: 23 March 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The nonequilibrium Green’s function approach is applied to the design of three-well indirect pumping terahertz (THz) quantum cascade lasers (QCLs) based on a resonant phonon depopulation scheme. The effects of the anticrossing of the injector states and the dipole matrix element of the laser levels on the optical gain of THz QCLs are studied. The results show that a design that results in a more pronounced anticrossing of the injector states will achieve a higher optical gain in the indirect pumping scheme compared to the traditional resonant-tunneling injection scheme. This offers in general a more efficient coherent resonant-tunneling transport of electrons in the indirect pumping scheme. It is also shown that, for operating temperatures below 200 K and low lasing frequencies, larger dipole matrix elements, i.e., vertical optical transitions, offer a higher optical gain. In contrast, in the case of high lasing frequencies, smaller dipole matrix elements, i.e., diagonal optical transitions are better for achieving a higher optical gain.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close