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

29 Oct 2001

Volume 79, Issue 18, pp. 2865-3001

Return to All Sections
back to top
RSS Feeds

Polarization charges and polarization-induced barriers in AlxGa1−xN/GaN and InyGa1−yN/GaN heterostructures

L. Jia, E. T. Yu, D. Keogh, P. M. Asbeck, P. Miraglia, A. Roskowski, and R. F. Davis

Appl. Phys. Lett. 79, 2916 (2001); http://dx.doi.org/10.1063/1.1412594 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polarization charges are measured and the formation of large electrostatic barriers arising primarily as a consequence of the presence of polarization-induced charge densities is deduced from capacitance–voltage analysis of n-type AlxGa1−xN/GaN and InyGa1−yN/GaN heterostructures. In structures consisting of 5–10 nm AlxGa1−xN or InyGa1−yN surrounded by n-GaN, capacitance–voltage profiling studies combined with elementary electrostatic analysis yield experimental estimates of polarization charge densities, which are compared with values expected based on the combined effects of spontaneous and piezoelectric polarization. These results imply the existence of electrostatic barriers that are due primarily to the large polarization charge densities at each heterojunction interface and the resulting potential difference maintained across the thin AlxGa1−xN or InyGa1−yN layers. The electrostatic barriers formed in these structures are large in comparison to the heterojunction conduction-band offsets, demonstrating the utility of polarization-based engineering of electrostatic barriers in nitride semiconductor heterostructures. © 2001 American Institute of Physics.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Electric field-induced junctions in epitaxial layers of CuInSe2

Konstantin Gartsman, David Cahen, and Roland Scheer

Appl. Phys. Lett. 79, 2919 (2001); http://dx.doi.org/10.1063/1.1415040 (3 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxial films of CuInSe2 on Si(111) were modified by the application of an electric field through a movable tip. The electric field induces stable junction regions which are identified by efficient separation and collection of electron beam-induced charge carriers. The movable tip allows for scribing of these junction regions. The junctions can be explained by symmetrical p/p+/n/p+/p regions formed within the CuInSe2 epilayers. The reported method presents an alternate way for junction patterning in two dimensions. © 2001 American Institute of Physics.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.05.Hd Other semiconductors

Defect annealing in Cu(In,Ga)Se2 heterojunction solar cells after high-energy electron irradiation

A. Jasenek, H. W. Schock, J. H. Werner, and U. Rau

Appl. Phys. Lett. 79, 2922 (2001); http://dx.doi.org/10.1063/1.1415345 (3 pages) | Cited 12 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cu(In,Ga)Se2/CdS/ZnO solar cells need at least 1018 cm−2 electrons of an energy of 1 MeV to degrade in their power conversion efficiency by more than 25%. Even after such high irradiation doses, annealing of the irradiated solar cells at temperatures between 130 and 160 °C leads to a full recovery of the device performance. Isochronal annealing experiments unveil that the annealing of the irradiation-induced defects has an activation energy of 1.05 eV. © 2001 American Institute of Physics.
Show PACS
84.60.Jt Photoelectric conversion
61.72.Cc Kinetics of defect formation and annealing

Low-resistance and high-transparency Ni/indium tin oxide ohmic contacts to p-type GaN

Ray-Hua Horng, Dong-Sing Wuu, Yi-Chung Lien, and Wen-How Lan

Appl. Phys. Lett. 79, 2925 (2001); http://dx.doi.org/10.1063/1.1415048 (3 pages) | Cited 78 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The characteristics of Ni/indium tin oxide (ITO) ohmic contacts to p-type GaN ( ∼ 2×1017 cm−3) have been studied. The Ni/ITO (10 nm/250 nm) layers were prepared by thermal evaporation and rf magnetron sputtering, respectively. Although the as-deposited Ni/ITO contacts present rectified behavior, the linear current–voltage characteristics can be obtained. The contact resistance can be reduced significantly for the ITO/Ni/p-GaN samples after suitable rapid thermal process. The contact property of ITO/Ni/p-GaN shows lowest specific contact resistivity of 8.6×10−4 Ω cm2 and high transparency (above 80% for 450–550 nm) as the sample annealed at 600 °C in air. Possible mechanisms for the observed low contact resistance and high transparency will be discussed. The present process is compatible with the fabrication for the high-efficient GaN light-emitting devices. © 2001 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.40.Cg Contact resistance, contact potential
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.72.Cc Kinetics of defect formation and annealing

Strain relief by long line defects in tensile GaxIn1−xP layers grown on InP substrates

M. Kahn and D. Ritter

Appl. Phys. Lett. 79, 2928 (2001); http://dx.doi.org/10.1063/1.1412587 (3 pages) | Cited 1 time

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fully strained layers of GaInP on InP significantly thicker than the theoretical critical thickness were grown by metalorganic molecular beam epitaxy. The excess strain energy of these layers is most probably accommodated by long line defects observed by atomic force microscopy. The thickness at which the long line defects appear is about four times the Matthews and Blakeslee critical thickness [J. W. Matthews and A. E. Blakeslee, J. Cryst. Growth 27, 118 (1974)]. Partial relaxation is measured by x-ray at about 14 times the theoretical critical thickness. © 2001 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties
81.05.Ea III-V semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Lk Linear defects: dislocations, disclinations
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Very-low-energy electron microscopy of doped semiconductors

M. M. El-Gomati and T. C. R. Wells

Appl. Phys. Lett. 79, 2931 (2001); http://dx.doi.org/10.1063/1.1415045 (3 pages) | Cited 22 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Imaging of As- and B-doped silicon regions has been performed in a scanning electron microscope operated in the cathode lens mode, with incident electron energies (EP) as low as 15 eV. The doped regions of n+ (As, 2.5×1020 cm−3) and p+ (B, 8×1019 cm−3) on n-type silicon ( ∼ 1015 cm−3) show distinct contrast with electron energies of about 3 keV. The brightest region is n+ followed by p+, then the n-type substrate. The highest contrast for the p+ and n+ type regions is reached at about EP = 300 and 15 eV, respectively. The contrast mechanisms are explained in terms of metal-semiconductor contact assuming an adventitious carbon film at the surface. © 2001 American Institute of Physics.
Show PACS
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
61.72.uf Ge and Si
79.20.Fv Electron impact: Auger emission
68.49.Jk Electron scattering from surfaces
73.40.Ns Metal-nonmetal contacts
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

Mass-density-modulated structures of crystalline hydrogenated carbon films

Z. J. Zhang, K. Narumi, and H. Naramoto

Appl. Phys. Lett. 79, 2934 (2001); http://dx.doi.org/10.1063/1.1411990 (3 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Hydrogenated carbon films with a crystalline structure have been synthesized by radio-frequency plasma-enhanced chemical vapor deposition. The mass density of the films is dependent on the plasma power applied. By switching alternatively two different plasma powers during deposition, mass-density-modulated structures of the crystalline hydrogenated carbon films can be produced. The structure and properties of these mass-density-modulated structures have also been investigated. © 2001 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.05.U- Carbon/carbon-based materials
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
52.77.Dq Plasma-based ion implantation and deposition
68.60.Bs Mechanical and acoustical properties

Recombination activity of copper in silicon

R. Sachdeva, A. A. Istratov, and E. R. Weber

Appl. Phys. Lett. 79, 2937 (2001); http://dx.doi.org/10.1063/1.1415350 (3 pages) | Cited 27 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The carrier recombination activity of copper in n-type and p-type silicon has been investigated. The minority carrier diffusion length has been found to decrease monotonically with increasing copper concentration in n Si and to exhibit a step-like behavior in p-type silicon at Cu concentrations above a certain critical level. It is suggested that the impact of copper on the minority carrier diffusion length is determined by the formation of copper precipitates. This process is retarded in perfect silicon due to the large lattice mismatch between Cu3Si and the silicon lattice and even more retarded in p Si, due to electrostatic repulsion effects between the positively charged copper precipitates and interstitial copper ions. Comparison of the impact of Cu on minority carrier diffusion length obtained with p-Si samples of different resistivity confirmed the electrostatic model. Studies of the impact of copper on minority carrier diffusion length in samples with internal gettering sites indicated that they provide heterogeneous nucleation sites for Cu precipitation at subcritical Cu concentration. Above a certain threshold of Cu concentration, the bulk recombination activity is dominated by quasihomogeneous formation of Cu precipitates, a process that is not detectably affected by the presence of oxide precipitates. © 2001 American Institute of Physics.
Show PACS
72.80.Cw Elemental semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
64.75.-g Phase equilibria
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close