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

17 Dec 2001

Volume 79, Issue 25, pp. 4073-4251

Return to All Sections
back to top
RSS Feeds

Direct observation of Fermi-level pinning in Cs-doped CuPc film

Li Yan, N. J. Watkins, S. Zorba, Yongli Gao, and C. W. Tang

Appl. Phys. Lett. 79, 4148 (2001); http://dx.doi.org/10.1063/1.1426260 (3 pages) | Cited 53 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic structures of pristine and Cs-doped CuPc films are investigated using photoemission spectroscopy and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital can be directly observed by IPES and ultraviolet photoemission spectroscopy simultaneously. We found that the Fermi-level position in organic film can be modified by Cs doping. The observed onset of the LUMO of the CuPc film is shifted by Cs doping to less than 0.2 eV above the Fermi level. The result indicates that the energy alignment and charge injection properties of the organic materials can be modified by a simple doping process. © 2001 American Institute of Physics.
Show PACS
71.20.Rv Polymers and organic compounds
73.61.Ph Polymers; organic compounds
79.60.Dp Adsorbed layers and thin films
71.55.Ht Other nonmetals
78.70.-g Interactions of particles and radiation with matter

Dislocation-free and lattice-matched Si/GaP1−xNx/Si structure for photo-electronic integrated systems

Kenji Momose, Hiroo Yonezu, Yasuhiro Fujimoto, Yuzo Furukawa, Yoshifumi Motomura, and Kunio Aiki

Appl. Phys. Lett. 79, 4151 (2001); http://dx.doi.org/10.1063/1.1425451 (3 pages) | Cited 23 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We proposed a Si/III–V–N compound semiconductors/Si structure, which is applicable to optoelectronic integrated circuits (OEICs). The feature of this structure is that optoelectronic devices and Si electronic devices could be fabricated by low-temperature planar process at the same time. A dislocation-free and lattice-matched Si/GaP1−xNx/Si (x = 2.9%) structure, which is a basic structure for OEICs, was grown by molecular-beam epitaxy. The images of transmission electron microscopy revealed that there were no threading dislocations and misfit dislocations in the epitaxial layers. It was clarified that the Si and GaP1−xNx layers were lattice-matched to Si and had structural high crystalline quality comparable to Si substrates. © 2001 American Institute of Physics.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.60.Bt Optoelectronic device characterization, design, and modeling
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.65.Ac Multilayers

Space-charge-limited currents in materials with Gaussian energy distributions of localized states

V. I. Arkhipov, P. Heremans, E. V. Emelianova, and G. J. Adriaenssens

Appl. Phys. Lett. 79, 4154 (2001); http://dx.doi.org/10.1063/1.1424046 (3 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A model is formulated describing trap-controlled space-charge-limited currents (SCLCs) in an organic material with a Gaussian density-of-states (DOS) distribution. It is shown that SCLC is not always controlled by carrier release from localized states around the Fermi level and, therefore, a Gaussian DOS can serve as either shallow or deep distribution of localized states depending upon the carrier and/or current density. © 2001 American Institute of Physics.
Show PACS
72.20.Ht High-field and nonlinear effects
71.55.Jv Disordered structures; amorphous and glassy solids
71.20.Rv Polymers and organic compounds
73.50.Fq High-field and nonlinear effects

Thermoelectric power of nitrogen-incorporated tetrahedral amorphous-carbon films

Somnath Bhattacharyya, F. Richter, U. Starke, H. Griessmann, and A. Heinrich

Appl. Phys. Lett. 79, 4157 (2001); http://dx.doi.org/10.1063/1.1426696 (3 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Tetrahedral amorphous-carbon (ta-C) films were deposited using a filtered cathodic vacuum arc in which nitrogen was incorporated up to an atomic fraction (fN) of 30%. Electrical conductivity and specially thermoelectric power (S) have been performed over a wide range of temperature. The room-temperature conductivity of these samples initially increases with fN up to several orders of magnitude compared to that of ta-C, followed by no dramatic change at higher nitrogen concentration. The sign of the S is negative in the samples with fN below ∼17%, then changes to a positive value with a higher fN. From thermal annealing of the nitrogenated samples a change of the sign of S and its dependence on fN has been analyzed. The small values of both room-temperature S and small variation of conductivity at high fN in all the samples suggest that electrical properties of these films are controlled by compensation of defects. © 2001 American Institute of Physics.
Show PACS
73.61.Jc Amorphous semiconductors; glasses
61.43.Dq Amorphous semiconductors, metals, and alloys
73.50.Lw Thermoelectric effects
71.55.Jv Disordered structures; amorphous and glassy solids
81.05.U- Carbon/carbon-based materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Simultaneous determination of Poisson ratio, bulk lattice constant, and composition of ternary compounds: In0.3Ga0.7As, In0.3Al0.7As, In0.7Ga0.3P, and In0.7Al0.3P

W. E. Hoke, T. D. Kennedy, and A. Torabi

Appl. Phys. Lett. 79, 4160 (2001); http://dx.doi.org/10.1063/1.1425954 (3 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A technique using the common (004) x-ray diffraction spectrum is demonstrated for the simultaneous determination of Poisson ratio, bulk lattice constant, and alloy composition for ternary compounds with lattice constants near the midpoint between GaAs and InP. Thin, strained layers of InGaAs, InAlAs, InGaP, and InAlP were grown. By careful choice of ternary composition and thickness, the same composition was grown on both GaAs and InP substrates without measurable relaxation in the (004) x-ray spectrum. The diffraction equation was simultaneously solved for the Poisson ratio and bulk lattice constant of the ternary compound. Subsequently the ternary composition was determined by applying Vegard’s law. The resulting Poisson ratios agreed well with the compositional averages of the binary endpoints. By extrapolating the results for InAlAs, a Poisson ratio of 0.33 was determined for AlAs. © 2001 American Institute of Physics.
Show PACS
62.20.D- Elasticity
61.66.Fn Inorganic compounds
81.40.Jj Elasticity and anelasticity, stress-strain relations

On the stability of organic field-effect transistor materials

Jan Hendrik Schön

Appl. Phys. Lett. 79, 4163 (2001); http://dx.doi.org/10.1063/1.1421230 (2 pages) | Cited 7 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stability and degradation of transistor performance of devices based on pentacene and α-sexithiophene are investigated. In order to distinguish between effects at grain boundaries and material issues, macroscopic bicrystals were used, where transistors were prepared on a single grain as well as across a single grain boundary. The main reason for performance instabilities is the formation of oxygen-related trapping states at the grain boundary upon exposure to air. However, especially in the case of pentacene, stable hole transport properties are observed. © 2001 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
61.72.Mm Grain and twin boundaries
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.50.Dn Low-field transport and mobility; piezoresistance

Effects of partial substitution of Ni by Pd on the thermoelectric properties of ZrNiSn-based half-Heusler compounds

Q. Shen, L. Chen, T. Goto, T. Hirai, J. Yang, G. P. Meisner, and C. Uher

Appl. Phys. Lett. 79, 4165 (2001); http://dx.doi.org/10.1063/1.1425459 (3 pages) | Cited 96 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the effects of partial substitution of nickel by palladium on the thermoelectric properties of ZrNiSn-based half-Heusler compounds. It is shown that the substitution of palladium for nickel results in a significant, beneficial reduction of the thermal conductivity. The Seebeck coefficient also decreases, but only by a small amount. In the Hf0.5Zr0.5Ni0.8Pd0.2Sn0.99Sb0.01 compound, a power factor of 22.1 μW K−2 cm−1 and a thermal conductivity as low as 4.5 W/m K are measured at room temperature. The dimensionless figure of merit ZT increases with increasing temperature and reaches a maximum value of 0.7 at about 800 K. © 2001 American Institute of Physics.
Show PACS
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys
72.15.Jf Thermoelectric and thermomagnetic effects

Composition dependence of the energy gap of Zn1−x−yMgxBeySe quaternary alloys nearly lattice matched to GaAs

K. Godo, H. Makino, M. W. Cho, J. H. Chang, Y. Yamazaki, T. Yao, M. Y. Shen, and T. Goto

Appl. Phys. Lett. 79, 4168 (2001); http://dx.doi.org/10.1063/1.1424064 (3 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The composition dependence of the energy gap (Eg) of Zn1−x−yMgxBeySe quaternary alloys grown by molecular-beam epitaxy was investigated. The energy gap of Zn1−x−yMgxBeySe can be controlled in a range of 2.7 eV<Eg<3 eV under nearly lattice-matching conditions to GaAs(001). The phenomenological formula for the energy gap of ZnMgBeSe quarterly is obtained using the bowing parameters theoretically or experimentally estimated for the ternary compounds. These results show that nonlinear behavior was observed on the composition dependence of the energy gap as the Be and Mg compositions increased. © 2001 American Institute of Physics.
Show PACS
71.20.Nr Semiconductor compounds
68.55.Nq Composition and phase identification
81.05.Dz II-VI semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors

Effects of arsenic concentration profile in gate oxide on electric properties of metal–oxide–silicon devices

Kuei-Shu Chang-Liao and Ching-Sang Chuang

Appl. Phys. Lett. 79, 4171 (2001); http://dx.doi.org/10.1063/1.1427132 (3 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of arsenic concentration profiles in gate oxides on the electrical properties of metal–oxide–silicon (MOS) capacitors were investigated. It is found that arsenic in the bulk of gate oxide degrades the electric property of MOS devices, which could be due to the electron traps introduced by arsenic. Interestingly, the electric properties of MOS devices can be improved by an increase in the arsenic concentration at the SiO2/Si interface. This improvement may be attributed to the interfacial strain relaxation and/or the replacement of nonbridging bonds. The arsenic concentration profile in gate oxide plays a crucial role for the electric properties of MOS devices. © 2001 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
61.72.S- Impurities in crystals
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close