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 2005

Volume 86, Issue 22, Articles (22xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 86, 223902 (2005); http://dx.doi.org/10.1063/1.1938253 (3 pages)

Philip J. Lee, Paul J. Hung, Robin Shaw, Lily Jan, and Luke P. Lee
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Phonon lifetimes and phonon decay in InN

J. W. Pomeroy, M. Kuball, H. Lu, W. J. Schaff, X. Wang, and A. Yoshikawa

Appl. Phys. Lett. 86, 223501 (2005); http://dx.doi.org/10.1063/1.1940124 (3 pages) | Cited 37 times

Online Publication Date: 24 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the Raman analysis of A1(LO) (longitudinal optical) and E2 phonon lifetimes in InN and their temperature dependence from 80 to 700 K. Our experimental results show that among the various possible decay channels, the A1(LO) phonon decays asymmetrically into a high energy and a low energy phonon, whereas the E2 phonon predominantly decays into three phonons. Possible decay channels of the A1(LO) phonon may involve combinations of transverse optical and acoustic phonons. Phonon lifetimes of 1.3 and 4 ps were measured at 80 K for the A1(LO) and the E2 phonons, respectively. This rather long A1(LO) phonon lifetime suggests that hot phonon effects will play a role in InN for carrier relaxation.
Show PACS
63.20.D- Phonon states and bands, normal modes, and phonon dispersion
78.30.Fs III-V and II-VI semiconductors
78.66.Fd III-V semiconductors

Electroluminescence from metal/oxide/strained-Si tunneling diodes

M. H. Liao, M.-J. Chen, T. C. Chen, P.-L. Wang, and C. W. Liu

Appl. Phys. Lett. 86, 223502 (2005); http://dx.doi.org/10.1063/1.1937989 (3 pages) | Cited 25 times

Online Publication Date: 24 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The metal-oxide-silicon light-emitting diode under biaxial tensile mechanical strain is studied. The emission line shape of the device can be fitted by the electron-hole-plasma recombination model. The energy gap of strained Si extracted by the light emission spectra at the temperature of 120 K is reduced by 15 meV under 0.13% biaxial tensile strain. The light intensity of the device under 0.13% biaxial tensile strain increases 9% as compared to the relaxed-Si device. The upshift of valence band edge under mechanical strain to increase the majority hole concentration at the oxide/Si interface may be responsible for this light emission enhancement. The mechanical strain is measured by Raman spectroscopy, strain gauge, and analyzed by the finite element method.
Show PACS
85.60.Jb Light-emitting devices
85.30.-z Semiconductor devices

Thin-film encapsulation of organic light-emitting devices

A. P. Ghosh, L. J. Gerenser, C. M. Jarman, and J. E. Fornalik

Appl. Phys. Lett. 86, 223503 (2005); http://dx.doi.org/10.1063/1.1929867 (3 pages) | Cited 46 times

Online Publication Date: 24 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Organic light-emitting devices (OLED) are extremely sensitive to moisture and oxygen. Without high-performance hermetic seals, the life of these devices is limited. Bottom-emitter OLEDs are commonly sealed using epoxy and cover glass with large amounts of desiccant. In top-emitter OLEDs the light passes through the cover glass on which the desiccant typically resides. Thus, transparent thin-film encapsulation without any desiccant is most desirable. This paper reports the results of a robust thin-film encapsulation method that utilizes a layer of aluminum oxide deposited by atomic layer deposition (ALD) process as the primary moisture barrier. More than 1000 h in 85 °C and 85% RH testing has been observed without significant device degradation caused by moisture. Data corroborating this method's superiority over other physical deposition methods for OLED encapsulation are also presented.
Show PACS
85.60.Jb Light-emitting devices
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Ultrathin epitaxial germanium on crystalline oxide metal-oxide-semiconductor-field-effect transistors

E. J. Preisler, S. Guha, B. R. Perkins, D. Kazazis, and A. Zaslavsky

Appl. Phys. Lett. 86, 223504 (2005); http://dx.doi.org/10.1063/1.1941451 (3 pages) | Cited 12 times

Online Publication Date: 26 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultrathin films of single crystal Ge (100 Å or less) have been grown epitaxially on a lattice matched high-κ crystalline oxide, lanthanum-yttrium-oxide, in turn grown on Si. Back-gated germanium-on-insulator field-effect transistors have been fabricated and measured from these germanium-on-insulator layers for Ge layers in the 30-600 Å range. The best devices exhibit an Ion/Ioff ratio over 103 at room temperature and 105 at T = 77 K. These ultrathin devices can be fully depleted and inverted, enabling both p and n channel operation in the same device.
Show PACS
85.30.Tv Field effect devices

Self-assembled monolayer modification of indium tin oxide anode surface for polymer light-emitting diodes with poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] for high performance

Chung-Chin Hsiao, Chih-Hao Chang, Ming-Chin Hung, Neng-Jye Yang, and Show-An Chen

Appl. Phys. Lett. 86, 223505 (2005); http://dx.doi.org/10.1063/1.1942644 (3 pages) | Cited 18 times

Online Publication Date: 26 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate that introducing a self-assembled monolayer (SAM) derived from 1,1,1,3,3,3-hexamethyldisilazane on an indium tin oxide (ITO) anode surface for the device (ITO/SAM/poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene]/Ca/Al), can lead to an improvement in maximum device efficiency from 2.0 to 3.9 cd/A and maximum brightness from 33 000 to 34 400 cd/m2. Such improvement is even better than that with introducing a layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (2.6 cd/A and 16 000 cd/m2), which is usually used as a hole transport (or injection) layer. The improvement results from a hole blocking effect and better wetting by converting the ITO surface from hydrophilic to hydrophobic provided by the SAM.
Show PACS
85.60.Jb Light-emitting devices
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials

An infrared probe of tunable dielectrics in metal-oxide-semiconductor structures

Z. Q. Li, G. M. Wang, K. J. Mikolaitis, D. Moses, A. J. Heeger, and D. N. Basov

Appl. Phys. Lett. 86, 223506 (2005); http://dx.doi.org/10.1063/1.1942645 (3 pages) | Cited 6 times

Online Publication Date: 26 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A composite metal-polymer electrode is designed to investigate electric-field-induced changes of the dielectric function of gate insulators in metal-oxide-semiconductor structures using infrared spectroscopy. We studied structures based on TiO2 dielectric insulator on doped silicon, a combination commonly used in field-effect transistors. It is shown that the voltage-induced changes of the dielectric constant in TiO2 originate from a modification of the lattice vibration modes of this compound.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
81.05.Cy Elemental semiconductors
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
78.30.Hv Other nonmetallic inorganics
77.22.Ch Permittivity (dielectric function)
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Intrinsic carrier effects in HfO2–Ge metal–insulator–semiconductor capacitors

A. Dimoulas, G. Vellianitis, G. Mavrou, E. K. Evangelou, and A. Sotiropoulos

Appl. Phys. Lett. 86, 223507 (2005); http://dx.doi.org/10.1063/1.1944227 (3 pages) | Cited 34 times

Online Publication Date: 27 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Germanium metal–insulator–semiconductor capacitors with HfO2 or other high-κ gate dielectrics show unusual low frequency behavior of the high frequency (1 kHz or higher) capacitance-voltage characteristics when biased in inversion. Here, we provide evidence that this effect is partly due to the high intrinsic carrier concentration ni in Ge. We show in particular that the ac conductance in inversion is thermally activated and it is governed either by generation-recombination processes in depletion, varying proportional to ni or by diffusion-limited processes varying as ni2, depending on whether the temperature is below or above 45 °C, respectively. From these measurements, we also show that the minority carrier response time in Ge is very short, in the microsecond range (much shorter than in Si), depending inversely proportional to ni at room temperature. This means that due to high ni, the inversion charge is built fast in response to high frequency signals at the gate, inducing the observed low frequency behavior.
Show PACS
84.32.Tt Capacitors
85.30.Tv Field effect devices
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Temperature stable LiNbO3 surface acoustic wave device with diode sputtered amorphous TeO2 over-layer

Namrata Dewan, Monika Tomar, Vinay Gupta, and K. Sreenivas

Appl. Phys. Lett. 86, 223508 (2005); http://dx.doi.org/10.1063/1.1944231 (3 pages) | Cited 5 times

Online Publication Date: 27 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Amorphous TeO2 thin film, sputtered in the O2+Ar(25%+75%) gas environment using a metallic tellurium target, has been identified as an attractive negative temperature coefficient of delay (TCD) material that can yield a temperature stable device when combined with a surface acoustic wave (SAW) device based on positive TCD material such as LiNbO3. The influence of amorphous TeO2 over-layer on the SAW propagation characteristics (velocity and temperature coefficient of delay) of the SAW filters (36 and 70 MHz) based on 128° rotated Y-cut X-propagating lithium niobate (128° Y‐X LiNbO3) single crystal has been studied. It is found that 0.042 λ thick TeO2 over-layer on a prefabricated SAW device operating at 36 MHz centre frequency, reduces the TCD of the device from 76 ppm °C−1 to almost zero ( ∼ 1.4 ppm °C−1) without deteriorating its efficiency and could be considered as a suitable alternative for temperature stable devices in comparison to conventional SiO2 over-layer.
Show PACS
43.58.Kr
81.15.Cd Deposition by sputtering

On the beneficial impact of tensile-strained silicon substrates on the low-frequency noise of n-channel metal-oxide-semiconductor transistors

E. Simoen, G. Eneman, P. Verheyen, R. Delhougne, R. Loo, K. De Meyer, and C. Claeys

Appl. Phys. Lett. 86, 223509 (2005); http://dx.doi.org/10.1063/1.1942631 (3 pages) | Cited 8 times

Online Publication Date: 27 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The low-frequency noise in n-channel metal-oxide-semiconductor field-effect transistors, fabricated on strained silicon (SSi) substrates has been investigated and compared with the results obtained on silicon reference wafers. The strained silicon was deposited on a thin strain-relaxed SiGe buffer layer. A 2-nm SiO2 layer was used as a gate dielectric. It is shown that a factor of 2–3 lower noise can be found in the SSi devices at a frequency f = 10 Hz, which appears to be correlated with the low-field mobility. This is interpreted in terms of the impact of the biaxial tensile strain on the gate oxide defectiveness.
Show PACS
85.30.Tv Field effect devices
85.30.De Semiconductor-device characterization, design, and modeling
81.05.Cy Elemental semiconductors
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Demonstration of undoped quaternary AlInGaN/GaN heterostructure field-effect transistor on sapphire substrate

Y. Liu, H. Jiang, S. Arulkumaran, T. Egawa, B. Zhang, and H. Ishikawa

Appl. Phys. Lett. 86, 223510 (2005); http://dx.doi.org/10.1063/1.1942643 (3 pages) | Cited 11 times

Online Publication Date: 27 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Undoped AlInGaN/GaN heterostructure field-effect transistors (HFETs) have been demonstrated on sapphire substrate. The maximum drain current of 758 mA/mm and extrinsic transconductance of 123 mS/mm were obtained from the device with 2 μm gate length and 15 μm gate width. Such performance was comparable to that of a conventional modulation-doped (MOD) AlGaN/GaN HFET fabricated at same the condition. In spite of the high-density two-dimentional electron gas formed at the heterointerface, the AlInGaN/GaN HFET structure showed relatively low Hall mobility (689 cm2/V s at 300 K), which was due to the high concentration background doping in the undoped AlInGaN barrier region. Encouragingly, both the gate leakage current and drain current collapse showed lower values than that of the MOD-AlGaN/GaN HFET, which implied the potential application of quaternary AlInGaN to high-power and high-frequency devices.
Show PACS
81.05.Ea III-V semiconductors
85.30.Tv Field effect devices
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.My Galvanomagnetic and other magnetotransport effects
61.72.uj III-V and II-VI semiconductors
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close