Device Physics

Behavior of Electronic Interferometers in the Nonlinear Regime

I. Neder and E. Ginossar
We investigate theoretically the behavior of the current oscillations in an electronic Mach-Zehnder interferometer (MZI) as a function of its source bias. Recently, the MZI visibility data showed an unexplained lobe pattern with a peculiar phase rigidity. Moreover, the effect did not depend on the M ... [Phys. Rev. Lett. 100, 196806 (2008)] published Fri May 16, 2008.

Nonequilibrium Dephasing in an Electronic Mach-Zehnder Interferometer

Seok-Chan Youn, Hyun-Woo Lee, and H.-S. Sim
We study nonequilibrium dephasing in an electronic Mach-Zehnder interferometer. We demonstrate that the shot noise at the beam splitter of the interferometer generates an ensemble of nonequilibrium electron density configurations and that electron interactions induce configuration-specific phase shi ... [Phys. Rev. Lett. 100, 196807 (2008)] published Fri May 16, 2008.

Slow Bloch modes for enhancing the absorption of light in thin films for photovoltaic cells

David Duche, Ludovic Escoubas, Jean-Jacques Simon, Philippe Torchio, Wilfried Vervisch et al.
This paper deals with the improvement of light harvesting in photovoltaic cells by using photonic nanostructures. We theoretically study a poly-3-hexylthiophene/[6,6]-phenyl-C61-butyric acid methyl ester (P3HT/PCBM) thin film periodically nanostructured in order to increase its absorption. The perio ... [Appl. Phys. Lett. 92, 193310 (2008)] published Thu May 15, 2008.

Green phosphorescent light-emitting diodes from polymer doped with iridium complex

Seung-Joon Lee, Jin Su Park, Myungkwan Song, Kyung-Jin Yoon, Young Inn Kim et al.
We demonstrate efficient organic light-emitting diodes by using a phosphorescent host/guest system consisting of a recently developed green electrophosphorescent molecule, bis[(4,6-difluorophenyl)-8-methylpyridinato-N,C2)iridium pyrazinate [(dfmppy)Irprz], as the guest and a blend of poly(N-vinylcar ... [Appl. Phys. Lett. 92, 193312 (2008)] published Thu May 15, 2008.

Enhancement of organic magnetoresistance by electrical conditioning

U. Niedermeier, M. Vieth, R. Patzold, W. Sarfert, and H. von Seggern
We demonstrate that electrical conditioning can be used as an efficient method to enhance the organic magnetoresistance effect in organic light emitting diodes. Depending on duration and intensity of the conditioning process the absolute value of the magnetoresistance effect can be increased from ~1 ... [Appl. Phys. Lett. 92, 193309 (2008)] published Thu May 15, 2008.

Bilayer processing for an enhanced organic-electrode contact in ultrathin bottom contact organic transistors

Jeongwon Park, Richard D. Yang, Corneliu N. Colesniuc, Amos Sharoni, Sungho Jin et al.
A bilayer lift-off process has been employed to fabricate optimal electrode contact geometry for statistical characterization of ultrathin organic thin-film transistors (OTFTs). For over 100 p-channel ultrathin (12 ML) copper phthalocyanine (CuPc) OTFTs, the bilayer photoresist lift-off process incr ... [Appl. Phys. Lett. 92, 193311 (2008)] published Thu May 15, 2008.

High efficiency and low efficiency roll off in white phosphorescent organic light-emitting diodes by managing host structures

Kyoung Soo Yook and Jun Yeob Lee
High efficiency phosphorescent white organic light-emitting diodes with little efficiency roll off were developed by managing the charge transport properties of the host materials. The emitting layers were stacked at a sequence of red/blue/green from the hole transport layer side and charge injectio ... [Appl. Phys. Lett. 92, 193308 (2008)] published Thu May 15, 2008.

A tunable all-fiber filter based on microfiber loop resonator

Wu Yu, Zeng Xu, Hou Changlun, Bai Jian, and Yang Guoguang
In this paper, a tunable high finesse microfilter is described, which is based on microfiber loop resonator (MLR). The length of microfiber loop could be controlled by a small cylindrical piezoelectric ceramic. As we calculated, this resonator has the maximum Q factor of 2400 and the finesse of 4.3. ... [Appl. Phys. Lett. 92, 191112 (2008)] published Thu May 15, 2008.

Effect of the barrier composition on the polarization fields in near UV InGaN light emitting diodes

A. Knauer, H. Wenzel, T. Kolbe, S. Einfeldt, M. Weyers et al.
The electroluminescence from near ultraviolet (UV) light emitting diodes containing InGaN multiple quantum wells (MQWs) with GaN, AlGaN, and InAlGaN barriers was investigated. Based on band-structure calculations the observed wavelength shift in the peak emission with increasing injection current is ... [Appl. Phys. Lett. 92, 191912 (2008)] published Thu May 15, 2008.

Carbon nanotube motors driven by carbon nanotube

Yoshiteru Takagi, Tsuyoshi Uda, and Takahisa Ohno
We propose a new type of carbon nanotube (CNT) motor composed of a single-wall CNT (SWCNT) and a double-wall CNT (DWCNT), that are in mechanical contact. The rotational motion of our CNT motor is controllable by the translational motion of the SWCNT along the axis of the DWCNT. From molecular dynami ... [J. Chem. Phys. 128, 194704 (2008)] published Thu May 15, 2008.

Thermal Conduction Switch for Thermal Management of Chip Scale Atomic Clocks (IMECE2006-14540)

A. D. Laws, Y. J. Chang, V. M. Bright, and Y. C. Lee
We report the first use of a bimetallic buckling disk as a thermal conduction switch. The disk is used to passively alter the thermal resistance of the package of a chip scale atomic clock. A vertical-cavity surface-emitting laser and a cesium vapor cell, contained in the clock, must be maintained a ... [J. Electron. Packag. 130, 021011 (2008)] published Thu May 15, 2008.

Experimental and Modeling of the Stress-Strain Behavior of a BGA Interconnect Due to Thermal Load

Yan Zhang, Johan Liu, and Ragnar Larsson
A plastic ball grid array component interconnect has been experimentally investigated and modeled on the basis of micropolar theory. The experimental results were analyzed, and the data also provided the verification for the micropolar interface model. Two different interconnect cross sections, name ... [J. Electron. Packag. 130, 021010 (2008)] published Thu May 15, 2008.

Fiber based organic photovoltaic devices

Brendan O'Connor, Kevin P. Pipe, and Max Shtein
A fiber-shaped organic photovoltaic cell is demonstrated, utilizing concentric thin films of small molecular organic compounds. Illuminated at normal incidence to the fiber axis through a thin metal electrode, the cell exhibits 0.5% power conversion efficiency, compared to 0.76% for a planar control ... [Appl. Phys. Lett. 92, 193306 (2008)] published Wed May 14, 2008.

Detection of chloride ions using an integrated Ag/AgCl electrode with AlGaN/GaN high electron mobility transistors

S. C. Hung, Y. L. Wang, B. Hicks, S. J. Pearton, D. M. Dennis et al.
AlGaN/GaN high electron mobility transistors (HEMTs) with an Ag/AgCl gate exhibit significant changes in channel conductance upon exposing the gate region to various concentrations of chloride (Cl) ion. The Ag/AgCl gate electrode, prepared by potentiostatic anodization, changes electrical potential ... [Appl. Phys. Lett. 92, 193903 (2008)] published Wed May 14, 2008.

ZnO metal-semiconductor field-effect transistors with Ag-Schottky gates

H. Frenzel, A. Lajn, M. Brandt, H. von Wenckstern, G. Biehne et al.
Metal-semiconductor field-effect transistors (MESFETs) were fabricated by reactive dc sputtering of Ag-Schottky gate contacts on ZnO thin-film channels grown by pulsed-laser deposition on sapphire. The n-type conductivity (normally on) of typical MESFETs is tunable over 8 decades in a voltage range ... [Appl. Phys. Lett. 92, 192108 (2008)] published Wed May 14, 2008.

Robust single-parameter quantized charge pumping

B. Kaestner, V. Kashcheyevs, G. Hein, K. Pierz, U. Siegner et al.
This paper investigates a scheme for quantized charge pumping based on single-parameter modulation. The device was realized in an AlGaAsGaAs gated nanowire. We find a remarkable robustness of the quantized regime against variations in the driving signal, which increases with applied rf power. This f ... [Appl. Phys. Lett. 92, 192106 (2008)] published Wed May 14, 2008.

Increased conductivity of a hole transport layer due to oxidation by a molecular nanomagnet

S. Cheylan, J. Puigdollers, H. J. Bolink, E. Coronado, C. Voz et al.
Thin film transistors based on polyarylamine poly(N,N-diphenyl-N,Nbis(4-hexylphenyl)-[1,1biphenyl]-4,4-diamine (pTPD) were fabricated using spin coating in order to measure the mobility of pTPD upon oxidation. Partially oxidized pTPD with a molecular magnetic cluster showed an increase in mobility o ... [J. Appl. Phys. 103, 096110 (2008)] published Wed May 14, 2008.

Organic light emitting diodes using a Ga:ZnO anode

J. J. Berry, D. S. Ginley, and P. E. Burrows
We report the application of gallium doped zinc oxide (GZO) films as anodes in organic light emitting diodes (OLEDs). Pulsed laser deposited GZO films of differing Ga composition are examined. Bilayer OLEDs using GZO and indium tin oxide (ITO) anodes are compared. Relative to ITO, the GZO anodes hav ... [Appl. Phys. Lett. 92, 193304 (2008)] published Tue May 13, 2008.

High quantum efficiency dots-in-a-well quantum dot infrared photodetectors with AlGaAs confinement enhancing layer

H. S. Ling, S. Y. Wang, C. P. Lee, and M. C. Lo
We demonstrate the high quantum efficiency InAs/InGaAs dots-in-a-well (DWELL) quantum dot infrared photodetectors (QDIPs). A thin AlGaAs layer was inserted on top of the InAs quantum dots (QDs) to enhance the confinement of QD states in the DWELL structure. The better confinement of the electronic s ... [Appl. Phys. Lett. 92, 193506 (2008)] published Tue May 13, 2008.

Gray-tone lithography using an optical diffuser and a contact aligner

Marc Christophersen and Bernard F. Phlips
This paper describes a simple method for the three-dimensional (3D) microfabrication of complex high-aspect structures in a one mask lithography process. The method relies on an unconventional way of performing gray-tone lithography. The main idea is to randomize the collimated light by using an opt ... [Appl. Phys. Lett. 92, 194102 (2008)] published Tue May 13, 2008.

Efficient suppression of charge trapping in ZnO-based transparent thin film transistors with novel Al[sub 2]O[sub 3]/HfO[sub 2]/Al[sub 2]O[sub 3] structure

Seongpil Chang, Yong-Won Song, Sanggyu Lee, Sang Yeol Lee, and Byeong-Kwon Ju
Charge trapping is dramatically suppressed in ZnO transparent thin film transistors (TFTs) employing a multilayered gate insulator with HfO layer sandwiched by AlO layers. In spite of its high dielectric constant, HfO has critical drawbacks including huge charge trap density in interfaces. We sugges ... [Appl. Phys. Lett. 92, 192104 (2008)] published Tue May 13, 2008.

Prepassivation surface treatment effects on pulsed and dc I-V performance of AlGaN/GaN high-electron-mobility transistors

David J. Meyer, Joseph R. Flemish, and Joan M. Redwing
This study has examined the effects that various prepassivation plasma surface treatments had on pulsed and dc I-V characteristics of AlGaN/GaN high-electron-mobility transistors. Pulsed I-V current recovery data indicates that CF, NH, O, and Cl plasma treatments can be used in conjunction with plas ... [Appl. Phys. Lett. 92, 193505 (2008)] published Tue May 13, 2008.

Silicon nanowire tunneling field-effect transistors

M. T. Bjork, J. Knoch, H. Schmid, H. Riel, and W. Riess
We demonstrate the implementation of tunneling field-effect transistors (TFETs) based on silicon nanowires (NWs) that were grown using the vapor-liquid-solid growth method. The Si NWs contain p-i-n segments that were achieved by in situ doping using phosphine and diborane as the n- and p-type dopant ... [Appl. Phys. Lett. 92, 193504 (2008)] published Tue May 13, 2008.

AlGaN/GaN High Electron Mobility Transistors Irradiated with 17 MeV Protons

Hong-Yeol Kim, Jihyun Kim, Sang Pil Yun, Kye Ryung Kim, Travis J. Anderson et al.
AlGaN/GaN high electron mobility transistors (HEMTs) with GaN cap layers were irradiated with high-energy (17 MeV) protons to doses up to 2 x 10 cm. There was no significant degradation in dc electrical parameters such as drainsource current (I) and extrinsic transconductance (g) of the HEMTs up t ... [J. Electrochem. Soc. 155, H513 (2008)] published Tue May 13, 2008.

Dependence of temperature and self-heating on electron mobility in ultrathin body silicon-on-insulator n-metal-oxide-semiconductor field-effect transistors

Tae-Hun Shim, Seong-Je Kim, Gon-Sub Lee, Kwan-Su Kim, Won-Ju Cho et al.
We investigated the dependence of temperature and self-heating on electron mobility in ultrathin body fully depleted silicon-on-insulator n-metal-oxide-semiconductor field-effect transistors as a function of silicon thickness by analyzing their electron states and electrical characteristics. We foun ... [J. Appl. Phys. 103, 094522 (2008)] published Tue May 13, 2008.

Fabrication and characterization of metal-ferroelectric (PbZr[sub 0.53]Ti[sub 0.47]O[sub 3])-Insulator (Y[sub 2]O[sub 3])-semiconductor field effect transistors for nonvolatile memory applications

Wen-Chieh Shih, Pi-Chun Juan, and Joseph Ya-min Lee
Metal-ferroelectric-insulator-semiconductor (MFIS) field effect transistors with Pb(Zr,Ti)O (PZT) ferroelectric layer and yttrium oxide YO insulator layer were fabricated. The maximum C-V memory window of 1.5 V was obtained at a sweep voltage of 8 V. The dominating conduction mechanism through the ... [J. Appl. Phys. 103, 094110 (2008)] published Tue May 13, 2008.

Conductor grid optimization for luminance loss reduction in organic light emitting diodes

Kristiaan Neyts, Alfonso Real, Matthias Marescaux, Saso Mladenovski, and Jeroen Beeckman
The recently increased efficiency of organic light emitting devices (OLED) brings lighting applications within reach. If the area of the OLED is of the order a cm, voltage and brightness losses related to the square resistance of the transparent electrode become important. The homogeneity of the vol ... [J. Appl. Phys. 103, 093113 (2008)] published Mon May 12, 2008.

Improvement of n-channel metal-oxide-semiconductor transistors by tensile stress despite increase in both on and subthreshold off currents

Peizhen Yang, W. S. Lau, Tiong Liang Ng, V. Ho, C. H. Loh et al.
We found that tensile stress actually increases both the on current and the subthreshold off current for n-channel metal-oxide-semiconductor transistors because of an increase in mobility. Our theory is that stress engineering works because the increase in the subthreshold off current can be easily ... [J. Appl. Phys. 103, 094518 (2008)] published Mon May 12, 2008.

Realization of ambipolar pentacene thin film transistors through dual interfacial engineering

Chuan-Yi Yang, Shiau-Shin Cheng, Chun-Wei Ou, You-Che Chuang, Meng-Chyi Wu et al.
Ambipolar conduction of a pentacene-based field-effect transistor can be attributed to dual interface engineering, which occurs at the dielectric/semiconductor interface and electrode/semiconductor interface. While the former was realized by utilizing a hydroxyl-free gate dielectric, the latter was ... [J. Appl. Phys. 103, 094519 (2008)] published Mon May 12, 2008.

Suppressing charge noise decoherence in superconducting charge qubits

J. A. Schreier, A. A. Houck, Jens Koch, D. I. Schuster, B. R. Johnson et al.
We present an experimental realization of the transmon qubit, which is an improved superconducting charge qubit derived from the Cooper pair box. We experimentally verify the predicted exponential suppression of sensitivity to 1/f charge noise. This removes the leading source of dephasing in charge ... [Phys. Rev. B 77, 180502 (2008)] published Mon May 12, 2008.

One-step preparation of Ca-alpha-SiAlON:Eu[sup 2+] fine powder phosphors for white light-emitting diodes

Takayuki Suehiro, Naoto Hirosaki, Rong-Jun Xie, Ken Sakuma, Mamoru Mitomo et al.
A simple methodology for producing yellow-emitting Ca-alpha-SiAlON:Eu phosphors for white light-emitting diodes has been developed, which consists of postsynthesis activation of fine alpha-SiAlON powders prepared by the gas-reduction-nitridation method. Phase-pure, fine Ca-alpha-SiAlON:Eu phosphors ... [Appl. Phys. Lett. 92, 191904 (2008)] published Mon May 12, 2008.

Ultrafast electron emission from metallic nanotip arrays induced by near infrared femtosecond laser pulses

S. Tsujino, P. Beaud, E. Kirk, T. Vogel, H. Sehr et al.
The authors explore the impact of femtosecond light pulses on the field-emission properties of single-gate molybdenum field-emitter arrays with nanometer scale tip apex. Despite the small fraction of the emission area, we observed a single-photon photoelectric current from the emitter tips on top of ... [Appl. Phys. Lett. 92, 193501 (2008)] published Mon May 12, 2008.

{110}-facets formation by hydrogen thermal etching on sidewalls of Si and strained-Si fin structures

Tsutomu Tezuka, Norio Hirashita, Yoshihiko Moriyama, Naoharu Sugiyama, Koji Usuda et al.
Si-fin structures for multigate metal-oxide-semiconductor field effect transistors (MOSFETs) with smooth and vertical sidewalls composed of {110} facets were obtained by an anisotropic gas etching in atmospheric hydrogen ambient at 9251000 degrees C on strained and unstrained (001) Si-on-insulator ... [Appl. Phys. Lett. 92, 191903 (2008)] published Mon May 12, 2008.

GaMnAs-based hybrid multiferroic memory device

M. Overby, A. Chernyshov, L. P. Rokhinson, X. Liu, and J. K. Furdyna
We report a nonvolatile hybrid multiferroic memory cell with electrostatic control of magnetization based on strain-coupled GaMnAs ferromagnetic semiconductor and a piezoelectric material. We use the crystalline anisotropy of GaMnAs to store information in the orientation of the magnetization along ... [Appl. Phys. Lett. 92, 192501 (2008)] published Mon May 12, 2008.

Tunnel spectroscopy in ac-driven quantum dot nanoresonators

J. Villavicencio, I. Maldonado, R. Sanchez, E. Cota, and G. Platero
Electronic transport in a triple quantum dot shuttle device in the presence of an ac field is analyzed within a fully quantum mechanical framework. A generalized density matrix formalism is used to describe the time evolution for electronic state occupations in a dissipative phonon bath. In the pres ... [Appl. Phys. Lett. 92, 192102 (2008)] published Mon May 12, 2008.

Current-Induced Torques Due to Compensated Antiferromagnets

Paul M. Haney and A. H. MacDonald
We analyze the influence of current-induced torques on the magnetization configuration of a ferromagnet in a circuit containing a compensated antiferromagnet. We argue that these torques are generically nonzero and determine their form by considering spin-dependent scattering at a compensated antife ... [Phys. Rev. Lett. 100, 196801 (2008)] published Mon May 12, 2008.

Inkjet printed polymer light-emitting devices fabricated by thermal embedding of semiconducting polymer nanospheres in an inert matrix

Evelin Fisslthaler, Stefan Sax, Ullrich Scherf, Gernot Mauthner, Erik Moderegger et al.
An aqueous dispersion of semiconducting polymer nanospheres was used to fabricate polymer light-emitting devices by inkjet printing in an easy-to-apply process with a minimum feature size of 20 [mu]m. To form the devices, the electroluminescent material was printed on a nonemitting polystyrene matr ... [Appl. Phys. Lett. 92, 183305 (2008)] published Fri May 9, 2008.

High performance light emitting transistors

Ebinazar B. Namdas, Peter Ledochowitsch, Jonathan D. Yuen, Daniel Moses, and Alan J. Heeger
Solution processed light emitting field-effect transistors (LEFETs) with peak brightness exceeding 2500 cd/m and external quantum efficiency of 0.15% are demonstrated. The devices utilized a bilayer film comprising a hole transporting polymer, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] th ... [Appl. Phys. Lett. 92, 183304 (2008)] published Fri May 9, 2008.

Hysteresis-free pentacene field-effect transistors and inverters containing poly(4-vinyl phenol-co-methyl methacrylate) gate dielectrics

Se Hyun Kim, Jaeyoung Jang, Hayoung Jeon, Won Min Yun, Sooji Nam et al.
The influence of hydroxyl groups on the hysteresis of pentacene field-effect transistors (FETs) and metal-insulator-semiconductor diodes containing poly(4-vinyl phenol) and poly(4-vinyl phenol-co-methyl methacrylate) (PVP-PMMA) gate dielectrics was investigated. The electrical characteristics and Fo ... [Appl. Phys. Lett. 92, 183306 (2008)] published Fri May 9, 2008.

Hybrid spacer for high-efficiency white organic light-emitting diodes

Ji Hoon Seo, Il Houng Park, Gu Young Kim, Kum Hee Lee, Min Kyu Kim et al.
High-efficient white organic light-emitting diodes (WOLEDs) were fabricated by using the following three different emitting materials: 4-(2,2-diphenylvinyl)-1-[4-(N,N-diphenylamino)-styryl]-terphenyl for blue emission, fac-tris(2-phenypyridine) iridium(III) for green emission, and bis(5-benzoyl-2-ph ... [Appl. Phys. Lett. 92, 183303 (2008)] published Fri May 9, 2008.

Photoinduced electron transfer in C[sub 60] encapsulated single-walled carbon nanotube

Y. F. Li, T. Kaneko, and R. Hatakeyama
The transport properties of field-effect transistors based on C fullerene peapods have been investigated and our findings indicate that the transport characteristics of single-walled carbon nanotubes (SWNTs) are highly sensitive to the encapsulated fullerenes due to the charge-transfer effect. Under ... [Appl. Phys. Lett. 92, 183115 (2008)] published Fri May 9, 2008.

Mechanism of flexural resonance frequency shift of a piezoelectric microcantilever sensor during humidity detection

Qing Zhu, Wan Y. Shih, and Wei-Heng Shih
We have examined the flexural resonance frequency shift of a piezoelectric microcantilever sensor (PEMS) during humidity detection and have shown that the flexural resonance frequency shift of the PEMS during detection was a result of Young's modulus change of its piezoelectric layer. Because of the ... [Appl. Phys. Lett. 92, 183505 (2008)] published Fri May 9, 2008.

Silicon depletion layer actuators

J. H. T. Ransley, A. Aziz, C. Durkan, and A. A. Seshia
The uncompensated donor or acceptor atoms present within the depletion layer of a diode can be employed in an electrostatic actuator, which utilizes the force between opposing charges on either side of the semiconductor junction. We describe the theory of this actuator and demonstrate its applicatio ... [Appl. Phys. Lett. 92, 184103 (2008)] published Fri May 9, 2008.

Electrical characterization of carbon nanotube field-effect transistors with SiN[sub x] passivation films deposited by catalytic chemical vapor deposition

Kenzo Maehashi, Yasuhide Ohno, Koichi Inoue, Kazuhiko Matsumoto, Toshikazu Niki et al.
SiN passivation films were deposited on carbon nanotube field-effect transistors (CNTFETs) by catalytic chemical vapor deposition (Cat-CVD) at low substrate temperatures. Deposition at 330 degrees C induced many defects in the CNT channels. The measurement of electrical properties revealed that p- ... [Appl. Phys. Lett. 92, 183111 (2008)] published Fri May 9, 2008.

High channel mobility 4H-SiC metal-oxide-semiconductor field-effect transistor with low temperature metal-organic chemical-vapor deposition grown Al[sub 2]O[sub 3] gate insulator

S. Hino, T. Hatayama, J. Kato, E. Tokumitsu, N. Miura et al.
Ultrahigh channel mobility is demonstrated for 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) with AlO gate insulators fabricated at low temperatures by metal-organic chemical-vapor deposition. Relatively high field effect channel mobility of 64 cm/V s is obtained when the AlO ... [Appl. Phys. Lett. 92, 183503 (2008)] published Fri May 9, 2008.

Terahertz Gunn-like oscillations in InGaAs/InAlAs planar diodes

S. Perez, T. Gonzalez, D. Pardo, and J. Mateos
A microscopic analysis of self-generated terahertz current oscillations that take place in planar InAlAs/InGaAs slot diodes operating under dc bias is presented. An ensemble Monte Carlo simulation is used for the calculations. The onset of the oscillations is thresholdlike, for drain-source voltages ... [J. Appl. Phys. 103, 094516 (2008)] published Fri May 9, 2008.

Structural and morphological properties of GaN buffer layers grown by ammonia molecular beam epitaxy on SiC substrates for AlGaN/GaN high electron mobility transistors

A. L. Corrion, C. Poblenz, F. Wu, and J. S. Speck
The impact of growth conditions on the surface morphology and structural properties of ammonia molecular beam epitaxy GaN buffers layers on SiC substrates was investigated. The threading dislocation (TD) density was found to decrease with decreasing NH:Ga flux ratio, which corresponded to an increas ... [J. Appl. Phys. 103, 093529 (2008)] published Fri May 9, 2008.

Wireless drive of a piezoelectric plate by capacitorlike structure in electric resonance with an inductor

Satyanarayan Bhuyan, Junhui Hu, and Chang Qing Sun
A new technique of wirelessly transmitting electric energy to piezoelectric components is explored. In the design, an ac electric field is focused to a piezoelectric plate placed between plate-shaped live and needle ground electrodes which form a capacitorlike electric field generator in series with ... [J. Appl. Phys. 103, 094915 (2008)] published Fri May 9, 2008.

Measurement of the junction temperature in high-power light-emitting diodes from the high-energy wing of the electroluminescence band

Z. Vaitonis, P. Vitta, and A. Zukauskas
By using pulsed driving currents with a small duty cycle, the high-energy wing of the electroluminescence band in AlGaInP and InGaN high-power light-emitting diodes (LEDs) was calibrated to measure the junction temperature in the range of 223358 K. In a red AlGaInP LED with a thick active layer, an ... [J. Appl. Phys. 103, 093110 (2008)] published Fri May 9, 2008.

On Failure Mechanisms in Flip Chip Assembly---Part 2: Optimal Underfill and Interconnecting Materials

Yoonchan Oh, C. Steve Suh, and Hung-Jue Sue
The physics explored in this investigation enables short-time scale dynamic phenomenon to be correlated with package failure modes such as solder ball cracking and interlayer debond. It is found that although epoxy-based underfills with nanofillers are shown to be effective in alleviating thermal st ... [J. Electron. Packag. 130, 021009 (2008)] published Fri May 9, 2008.

On Failure Mechanisms in Flip Chip Assembly---Part 1: Short-Time Scale Wave Motion

Yoonchan Oh, C. Steve Suh, and Hung-Jue Sue
The demand for higher clock speed and larger current magnitude in high-performance flip chip packaging configurations of small footprint has raised the concern over rapid thermal transients and large thermal spatial gradients that could severely compromise package performance. This paper explores co ... [J. Electron. Packag. 130, 021008 (2008)] published Fri May 9, 2008.