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

28 Jul 2003

Volume 83, Issue 4, pp. 593-811

Issue Cover Spotlight Figure

Appl. Phys. Lett. 83, 611 (2003); http://dx.doi.org/10.1063/1.1595724 (3 pages)

Chung-Chih Wu, Chieh-Wei Chen, and Ting-Yi Cho
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Efficiency enhancement of ideal photovoltaic solar cells by photonic excitations in multi-intermediate band structures

R. W. Peng, M. Mazzer, and K. W. J. Barnham

Appl. Phys. Lett. 83, 770 (2003); http://dx.doi.org/10.1063/1.1592881 (3 pages) | Cited 11 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present an efficiency analysis of ideal photovoltaic solar cells based on multi-intermediate band structures. It is shown that the difference between the thermodynamic limit of photovoltaic conversion and the limit of efficiency of traditional bulk semiconductor solar cells can be gradually bridged if an optimum energy band structure is achieved. Efficiency enhancement originates from photonic excitations among multiple energy bands. Several possible ways to design the optimum energy band structures are proposed. © 2003 American Institute of Physics.
Show PACS
84.60.Jt Photoelectric conversion
73.20.At Surface states, band structure, electron density of states

Influence of surface oxides on hydrogen-sensitive Pd:GaN Schottky diodes

O. Weidemann, M. Hermann, G. Steinhoff, H. Wingbrant, A. Lloyd Spetz, M. Stutzmann, and M. Eickhoff

Appl. Phys. Lett. 83, 773 (2003); http://dx.doi.org/10.1063/1.1593794 (3 pages) | Cited 36 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The hydrogen response of Pd:GaN Schottky diodes, prepared by in situ and ex situ deposition of catalytic Pd Schottky contacts on Si-doped GaN layers is compared. Ex situ fabricated devices show a sensitivity towards molecular hydrogen, which is about 50 times higher than for in situ deposited diodes. From the analysis of these results, we conclude that adsorption sites for atomic hydrogen in Pd:GaN sensors are provided by an oxidic intermediate layer. In addition, in situ deposited Pd Schottky contacts reveal lower barrier heights and drastically higher reverse currents. We suggest that the passivation of the GaN surface before ex situ deposition of Pd also results in quenching of leakage paths caused by structural defects. © 2003 American Institute of Physics.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.30.Kk Junction diodes
68.43.Mn Adsorption kinetics
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.65.Rv Passivation
68.47.Fg Semiconductor surfaces
73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Ns Metal-nonmetal contacts

Bright red-emitting electrophosphorescent device using osmium complex as a triplet emitter

Joo Hyun Kim, Michelle S. Liu, Alex K.-Y. Jen, Brenden Carlson, Larry R. Dalton, Ching-Fong Shu, and Rajasekhar Dodda

Appl. Phys. Lett. 83, 776 (2003); http://dx.doi.org/10.1063/1.1593230 (3 pages) | Cited 43 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A series of efficient and bright double-layer light-emitting devices have been fabricated using the osmium (Os) complex as the triplet emissive dopant in both a blue-emitting polyfluorene derivative (PF–TPA–OXD) containing hole-transporting triphenylamine (TPA) and electron-transporting oxadiazole (OXD) as side chains and a blend of 2-(4-t-butylphenyl)-5(4-biphenylyl)-1,3,4-oxadizole (PBD) in poly(N-vinylcarbazole) (PVK). Due to a balanced charge injection and transport in PF–TPA–OXD and very efficient energy transfer from this polymer to the Os complex, the resulting device (indium tin oxide/HTL/OsCF3:PF–TPA–OXD/Ca/Ag) reaches a maximum external quantum efficiency of 2.1% with a peak brightness of 2920 cd/m2. These results are significantly higher than those obtained from the commonly used host, PVK:PBD (0.49% and 1270 cd/m2). © 2003 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices

Characteristics of ultrathin HfO2 gate dielectrics on strained-Si0.74Ge0.26 layers

Je-Hun Lee, S. Maikap, Doh-Y. Kim, R. Mahapatra, S. K. Ray, Y. S. No, and Won-Kook Choi

Appl. Phys. Lett. 83, 779 (2003); http://dx.doi.org/10.1063/1.1589165 (3 pages) | Cited 22 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structural and electrical characteristics of HfO2 gate dielectrics along with the interfacial layers formed on strained-Si0.74Ge0.26 films have been investigated. The polycrystalline HfO2 film with a physical thickness of ∼ 4.0 nm and an amorphous Hf–silicate interfacial layer with a physical thickness of ∼ 4.5 nm have been observed by high-resolution transmission electron microscopy and time-of-flight secondary ion mass spectroscopy. The electrical properties have been studied using metal–oxide–semiconductor (MOS) structures. A dielectric constant of 26 for HfO2 film and 8.0 for Hf–silicate interfacial layer have been calculated from the accumulation capacitances of the capacitors. These dielectrics show an equivalent oxide thickness as low as 0.6 nm for HfO2 and 2.2 nm for the Hf–silicate layers. The fabricated SiGe MOS capacitors show a low leakage current density of ∼ 6.5×10−7 A/cm2 at a gate voltage of −1.0 V, breakdown field of 6.5 MV/cm, and moderately low interface state density of 5.5×1011 cm−2 eV−1. © 2003 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
77.22.Ch Permittivity (dielectric function)
77.22.Jp Dielectric breakdown and space-charge effects

Effect of hydrogen dilution on the open-circuit voltage of hydrogenated amorphous silicon solar cells

Baojie Yan, Jeffrey Yang, and Subhendu Guha

Appl. Phys. Lett. 83, 782 (2003); http://dx.doi.org/10.1063/1.1595153 (3 pages) | Cited 7 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The open-circuit voltage (Voc) of hydrogenated amorphous silicon solar cells has been studied experimentally and by computer simulation. We find that band gap and defect states affect Voc significantly. Hydrogen (H2) dilution widens the band gap and reduces density of defect states; both contribute to larger Voc and better fill factor in H2 diluted solar cells. Valence band tail narrowing could affect Voc, but is not included in this study due to lack of available data. © 2003 American Institute of Physics.
Show PACS
84.60.Jt Photoelectric conversion
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
71.55.Cn Elemental semiconductors
71.55.Jv Disordered structures; amorphous and glassy solids

Monte Carlo simulations of Hg0.7Cd0.3Te avalanche photodiodes and resonance phenomenon in the multiplication noise

Feng Ma, Xiaowei Li, Joe C. Campbell, Jeffrey D. Beck, Chang-Feng Wan, and Michael A. Kinch

Appl. Phys. Lett. 83, 785 (2003); http://dx.doi.org/10.1063/1.1596727 (3 pages) | Cited 21 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monte Carlo simulations of Hg0.7Cd0.3Te avalanche photodiodes are presented. The simulated very low excess noise and exponential gain curve are consistent with those that have been experimentally observed and are consistent with the speculated large ratio of electron and hole impact ionization rates. The simulations suggest that there is a large difference between the scattering rates of electrons and holes, a direct consequence of the band structure. A resonance behavior in the excess noise factor at gain values near 2, 4, 8, and 16 is also revealed in the simulations. This effect is explained by comparing to the gain and noise of a photomultiplier tube. © 2003 American Institute of Physics.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
02.70.Uu Applications of Monte Carlo methods

Scaling limits of hafnium–silicate films for gate-dielectric applications

Hideki Takeuchi and Tsu-Jae King

Appl. Phys. Lett. 83, 788 (2003); http://dx.doi.org/10.1063/1.1594829 (3 pages) | Cited 8 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The scaling limits of hafnium–silicate (Hf–silicate) films for use as the gate dielectric material in complementary metal–oxide–semiconductor field-effect transistors are investigated. Scalability is gauged by a figure of merit taken from the analytical model for direct tunneling leakage current. Based on the compositional dependence of this figure of merit, pure HfO2 is more scalable than Hf–silicates. However, the formation of intermediate oxide layers at the Si interface can limit the scalability of HfO2 to ∼ 1.0 nm equivalent SiO2 thickness (EOT). The use of Si3N4 as a diffusion barrier can prevent the formation of these interfacial layers and thereby yield lower EOT. Alternatively, 20% Hf–silicate may be more scalable than pure HfO2 with interfacial oxide layers. © 2003 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
85.30.Tv Field effect devices
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Demonstration of a low-noise near-infrared photon counter with multiphoton discrimination

Aaron J. Miller, Sae Woo Nam, John M. Martinis, and Alexander V. Sergienko

Appl. Phys. Lett. 83, 791 (2003); http://dx.doi.org/10.1063/1.1596723 (3 pages) | Cited 78 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have demonstrated a system capable of directly measuring the photon-number state of a single pulse of light using a superconducting transition-edge sensor microcalorimeter. We verify the photon-number distribution of a weak pulsed-laser source at 1550 nm. Such single-photon metrology at telecommunication wavelengths provides the foundation for ensuring the security of photon sources used in implementations of quantum cryptography. Additionally, this system has the lowest noise equivalent power of any single-photon detector and combines high efficiency near-infrared photon counting with the ability to resolve multiphoton absorption events. © 2003 American Institute of Physics.
Show PACS
42.50.Ar Photon statistics and coherence theory
03.67.Dd Quantum cryptography and communication security
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Room-temperature electroluminescence of ion-beam-synthesized β-FeSi2 precipitates in silicon

Lucio Martinelli, E. Grilli, M. Guzzi, and M. G. Grimaldi

Appl. Phys. Lett. 83, 794 (2003); http://dx.doi.org/10.1063/1.1593815 (3 pages) | Cited 19 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple silicon-based electroluminescent device has been realized, embedding β-FeSi2 precipitates in the depletion region of a Si p–n junction by ion-beam synthesis, a process fully compatible with microelectronics technologies. Light emission peaked at about 1.6 μm has been observed up to room temperature. The luminescence signal is shown to be due to interband recombination in the crystalline nanoprecipitates. © 2003 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
85.60.Jb Light-emitting devices
61.72.uf Ge and Si
64.75.-g Phase equilibria
81.05.Hd Other semiconductors
78.55.Hx Other solid inorganic materials

Fabrication and coupling to planar high-Q silica disk microcavities

T. J. Kippenberg, S. M. Spillane, D. K. Armani, and K. J. Vahala

Appl. Phys. Lett. 83, 797 (2003); http://dx.doi.org/10.1063/1.1593833 (3 pages) | Cited 39 times

Online Publication Date: 22 July 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using standard lithographic techniques, we demonstrate fabrication of silica disk microcavities, which exhibit whispering-gallery-type modes having quality factors (Q) in excess of 1 million. Efficient coupling (high extinction at critical coupling and low, nonresonant insertion loss) to and from the disk structure is achieved by the use of tapered optical fibers. The observed high Q is attributed to the wedged-shaped edge of the disk microcavity, which is believed to isolate modes from the disk perimeter and thereby reduce scattering loss. The mode spectrum is measured and the influence of planar confinement on the mode structure is investigated. We analyze the use of these resonators for very low loss devices, such as add/drop filters. © 2003 American Institute of Physics.
Show PACS
42.82.Cr Fabrication techniques; lithography, pattern transfer
42.82.Et Waveguides, couplers, and arrays
42.81.Qb Fiber waveguides, couplers, and arrays
42.79.Ci Filters, zone plates, and polarizers
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close