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

9 Aug 2004

Volume 85, Issue 6, pp. 855-1088

Issue Cover Spotlight Figure

Appl. Phys. Lett. 85, 1072 (2004); http://dx.doi.org/10.1063/1.1781351 (3 pages)

Liang-Shan Chen, Chao-Hsien Kuo, and Zhen Ye
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Hopping versus bulk conductivity in transparent oxides: 12CaO⋅7Al2O3

J. E. Medvedeva and A. J. Freeman

Appl. Phys. Lett. 85, 955 (2004); http://dx.doi.org/10.1063/1.1781362 (3 pages) | Cited 20 times

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
First-principles calculations of the mayenite-based oxide, [Ca12Al14O32]2+(2e−), reveal the mechanism responsible for its high conductivity. A detailed comparison of the electronic and optical properties of this material with those of the recently discovered transparent conducting oxide, H-doped UV-activated Ca12Al14O33, allowed us to conclude that the enhanced conductivity in [Ca12Al14O32]2+(2e−) is achieved by elimination of the Coulomb blockade of the charge carriers. This results in a transition from variable range-hopping behavior with a Coulomb gap in H-doped UV-irradiated Ca12Al14O33, to bulk conductivity in [Ca12Al14O32]2+(2e−). Further, the high degree of delocalization of the conduction electrons obtained in [Ca12Al14O32]2+(2e−) indicates that it cannot be classified as an electride, as originally suggested.
Show PACS
72.20.Ee Mobility edges; hopping transport
73.23.Hk Coulomb blockade; single-electron tunneling
71.20.Ps Other inorganic compounds
71.15.-m Methods of electronic structure calculations
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Field-dependent charge carrier dynamics in GaN: Excitonic effects

J. van de Lagemaat, D. Vanmaekelbergh, and J. J. Kelly

Appl. Phys. Lett. 85, 958 (2004); http://dx.doi.org/10.1063/1.1779349 (3 pages) | Cited 1 time

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electric-field dependence of the charge-carrier dynamics in GaN was studied by measuring excitation spectra of the sub-band-gap (yellow) luminescence as a function of bias using a Schottky junction formed at the interface between the semiconductor and an electrolyte solution. At large bias, the contribution of free electrons and holes to the photoluminescence is significantly reduced due to the dead-layer effect. As a result, striking features are revealed in the spectra close to the fundamental absorption. These features are attributed to exciton decay via yellow luminescence centers.
Show PACS
78.66.Fd III-V semiconductors
73.50.Pz Photoconduction and photovoltaic effects
78.55.Cr III-V semiconductors
71.35.-y Excitons and related phenomena
85.30.Kk Junction diodes
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.40.Mr Semiconductor-electrolyte contacts

Band offset at the CuGaSe2∕In2S3 heterointerface

T. Schulmeyer, A. Klein, R. Kniese, and M. Powalla

Appl. Phys. Lett. 85, 961 (2004); http://dx.doi.org/10.1063/1.1779340 (3 pages) | Cited 3 times

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the electronic properties of the CuGaSe2∕In2S3 heterointerface by photoelectron spectroscopy. In2S3 was evaporated by physical vapor deposition onto contamination free polycrystalline CuGaSe2 surface prepared by the selenium decapping process. A valence band offset ΔEVB=0.78±0.1 has been determined.
Show PACS
71.20.Nr Semiconductor compounds
73.20.At Surface states, band structure, electron density of states
79.60.Jv Interfaces; heterostructures; nanostructures
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Observation of a 0.7 eV electron trap in dilute GaAsN layers grown by liquid phase epitaxy

S. Dhar, N. Halder, J. Kumar, and B. M. Arora

Appl. Phys. Lett. 85, 964 (2004); http://dx.doi.org/10.1063/1.1779346 (3 pages) | Cited 9 times

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The growth of GaAsN layers by liquid phase epitaxy, using polycrystalline GaN as the source of nitrogen, is reported. The presence of nitrogen in the grown layer is indicated by a nitrogen-related shoulder in the Fourier transform absorption spectrum and a resultant band-gap reduction of 90 meV is measured by optical transmission and photocurrent techniques. Data from photocurrent and photocapacitance measurements show the presence of a 0.7 eV electron trap in the material which originates due to nitrogen. Compared with earlier published data on GaAsN, grown by other techniques, the trap is tentatively related to (N–N) defects at As sites.
Show PACS
81.05.Ea III-V semiconductors
78.66.Fd III-V semiconductors
73.61.Ey III-V semiconductors
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
68.55.A- Nucleation and growth
71.55.Eq III-V semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
73.50.Pz Photoconduction and photovoltaic effects
78.30.Fs III-V and II-VI semiconductors

Y-branched Bi nanowires with metal–semiconductor junction behavior

Yongtao Tian, Guowen Meng, Sujit K. Biswas, Pulickel M. Ajayan, Shuhui Sun, and Lide Zhang

Appl. Phys. Lett. 85, 967 (2004); http://dx.doi.org/10.1063/1.1779956 (3 pages) | Cited 21 times

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Y-branched Bi nanowires (NWs) embedded in anodic aluminum oxide templates were synthesized by electrochemical deposition. Transmission electron microscope observations revealed that the “stem” and the “branches” of the Y-branched Bi NWs are about 80 and 50 nm in diameter, respectively. Selected area electron diffraction studies showed that both the stem and the branches are single crystalline. Current–voltage measurement revealed that the parallel Y-branched Bi NWs have characteristics of conventional metal–semiconductor junctions. Our approach to produce one-dimensional metal–semiconductor junctions using Y-branched NWs consisting of only one kind of semimetal and without any external doping can be exploited to create metal–semiconductor junctions of other semimetals, which may find various applications in nanodevices.
Show PACS
73.40.Ns Metal-nonmetal contacts
61.46.-w Structure of nanoscale materials
81.07.Bc Nanocrystalline materials

Effect of metal electrodes on the performance of polymer:fullerene bulk heterojunction solar cells

V. D. Mihailetchi, L. J. A. Koster, and P. W. M. Blom

Appl. Phys. Lett. 85, 970 (2004); http://dx.doi.org/10.1063/1.1782252 (3 pages) | Cited 54 times

Online Publication Date: 4 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An increase in the workfunction of the metal top electrode leads to a reduction of the open-circuit voltage, short-circuit current, and power conversion efficiency of organic bulk-heterojunction solar cells. It has been demonstrated that the photocurrent obtained from an active layer comprised of a blend of poly(2-methoxy-5-(3′,7′-dimethyloctyloxy)-p-phenylene vinylene) (OC1C10-PPV) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM), with lithium fluoride topped aluminum, silver, gold, or palladium electrodes, shows a universal behavior when scaled against the effective voltage across the device. Indeed, model calculations confirm that the dependence of the photocurrent on the effective voltage is responsible for the observed variation in performance of each different electrode. Consequently, for any given metal, only the device’s open-circuit voltage is required in order to be able to predict the remaining solar cell parameters.
Show PACS
84.60.Jt Photoelectric conversion
73.40.Cg Contact resistance, contact potential
73.61.Ph Polymers; organic compounds
81.05.ub Fullerenes and related materials
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close