Conductivity of the Granular Metal Films Obtained by High Dose Ion Implantation into Pmma

1995 ◽  
Vol 388 ◽  
Author(s):  
V.V. Bazarov ◽  
V.Yu. Petukhov ◽  
V.A. Zhikharev ◽  
I.B. Khaibullin
Keyword(s):  
Low Temperature ◽  
Ion Implantation ◽  
Temperature Dependence ◽  
Metal Films ◽  
High Dose ◽  
High Fluence ◽  
Granular Film ◽  
Satisfactory Explanation ◽  
Thermally Activated ◽  
Ions Implantation

AbstractThin granular metal films in polymethylmethacrylate(PMMA) have been synthesized by 40 keV Fe+, ag+ or Pb+ ions implantation with fluencies up to 6*1017 ion/cm2. the resistivity of synthesized films was measured in the temperature range from 300K. to 5K. the temperature dependence of the resistivity of PMMA implanted with ag+, Pb+ and small fluence Fe+ obeys the well known law lnR~(l/T)1/2. the samples implanted by high fluence Fe+ reveal rather a different behaviour. at low temperature (T<100K) the curves R(T) fit the formulae inR~lnT. the two mechanisms of conductivity of a granular film are considered: direct tunneling and thermally activated hopping. Combined with the morphology features of films, obtained by high fluence Fe+ implantation, the above mentioned consideration offers a satisfactory explanation of the observed temperature dependence R(T).

Electrical Measurement of the Bandgap of N+ and P+ SiGe Formed by Ge Ion Implantation

1997 ◽  
Vol 500 ◽  
Author(s):  
Akira Nishiyama ◽  
Osamu Arisumi ◽  
Makoto Yoshimi
Keyword(s):  
Ion Implantation ◽  
Theoretical Calculation ◽  
Temperature Dependence ◽  
Electrical Measurement ◽  
Bipolar Transistors ◽  
Floating Body ◽  
High Dose ◽  
Base Current ◽  
Source Regions ◽  
Heavily Doped

ABSTRACTN+ and p+ SiGe layers were formed in the source regions of SOI MOSFETs in order to suppress the floating-body effects by means of high-dose Ge implantation. The bandgaps of the layers were evaluated by measuring the temperature dependence of the base current of the source/channel/drain lateral bipolar transistors. It has been found that the reductions of the bandgaps due to the SiGe formation by the Ge implantation were relatively small, compared to those obtained by the theoretical calculation for heavily doped SiGe. It was also found that the bandgap reduction was larger for n+ layers than that for p+ layers.

Investigation of Polarization Mechanism of Relaxor Ferroelectrics

1996 ◽  
Vol 453 ◽  
Author(s):  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Yao Xi
Keyword(s):  
Dielectric Constant ◽  
Low Temperature ◽  
Temperature Dependence ◽  
High Precision ◽  
Relaxor Ferroelectrics ◽  
Dielectric Behavior ◽  
Polar Regions ◽  
Thermally Activated ◽  
Polarization Mechanism ◽  
Constant Maximum

AbstractAddition to thermally activated flips of polar regions in relaxor ferroelectrics, a new polarization mechanism, which originates from the vibrations (breathing) of surface of polar regions, is introduced to explain the dielectric behavior of relaxor ferroelectrics. This new mechanism plays an important role in the dielectric behavior of such materials at low temperature. Based on the above assumption and general dielectric theory, a formula is given to characterize the temperature dependence of the dielectric constant. The correctness of the formula is verified by using it to fit the experimental results of the two typical relaxors. The fitted results show that the method is of high precision and that the temperature of the dielectric constant maximum is decided by the two polarization behavior. It also indicates that the new polarization is a resonance polarization.

Temperature Dependence and Annealing Behaviour of Hf Implanted (100)Si: HfSi 2 Synthesis

1995 ◽  
Vol 402 ◽  
Author(s):  
M. R. Da Silva ◽  
A. A. Melo ◽  
J. C. Soares ◽  
M. F. Da Silva ◽  
R. Moons ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Substrate Temperature ◽  
Temperature Dependence ◽  
Subsequent Annealing ◽  
High Fluence ◽  
Annealing Behaviour

AbstractWe investigated the formation of a buried HfSi2 layer by high fluence ion implantation of isotopically mass separated 179–180 Hf+ on heated silicon (100) substrates. It is shown that for the substrate temperature of 600°C a buried HfSi 2 layer is formed. By subsequent annealing at 1000 °C a continuous 12 nm HfSi2 layer on the Si surface is formed followed by 130 nm big almost spherodized HfSi2 ellipsoid and 80 nm small HfSi2 and Si grains. The annealing of samples implanted at lower temperatures show that HfSi2 is also formed but with reduced yield. A summary of the relevant data is presented.

Ion Mixing of Near-Noble Transition Metal Films on Evaporated and Large-Grained Aluminum Substrates

1987 ◽  
Vol 93 ◽  
Author(s):  
E. Ma ◽  
X.-A. Zhao ◽  
M-A. Nicolet
Keyword(s):  
Low Temperature ◽  
Transition Metal ◽  
Temperature Dependence ◽  
Thermal Annealing ◽  
Phenomenological Model ◽  
Metal Films ◽  
Mixing Efficiency ◽  
Thermal Spike ◽  
Significant Difference ◽  
Aluminum Substrates

ABSTRACTIon mixing experiments using Xe ions at temperatures ranging from 77K to about 450K were conducted on Al/Ni and Al/Pt couples. Evaporated polycrystalline Al films and large-grained Al crystals were used as substrates. Xenon irradiation of Al/Pt bilayers achieves considerable intermixing and a temperature dependence is observed. Only moderate interfacial mixing with little temperature dependence is observed in Al/Ni bilayers. The mixing efficiency of Al/Ni is consistent with the phenomenological model of thermal spike mixing, and so is the absence of a pronounced temperature dependence below 450K. No significant difference is noted in ion mixing of evaporated and large-grained Al substrates. In contrast to ion mixing, Al/Pt and Al/Ni samples behave similarly upon thermal annealing and form well-defined compounds. The results are also compared with Si/metal systems, where silicides can be formed readily by low temperature thermal annealing as well as by ion mixing of bilayer samples.

Nanomechanical properties of energetically treated polyethylene surfaces

2002 ◽  
Vol 17 (2) ◽  
pp. 423-430 ◽  
Author(s):  
C. Klapperich ◽  
L. Pruitt ◽  
K. Komvopoulos
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Ion Implantation ◽  
Ion Beam ◽  
Plasma Modification ◽  
High Dose ◽  
Oxygen Ion ◽  
Ion Beam Treatment ◽  
Argon Ion ◽  
Oxygen Ion Implantation

The effects of energetic treatments, crosslinking, and plasma modification on the surface mechanical properties and deformation behavior of ultrahigh molecular weight polyethylene (UHMWPE) were examined in light of nanoindentation experiments performed with a surface force microscope. Samples of UHMWPE were subjected to relatively high-dose gamma irradiation, oxygen ion implantation, and argon ion beam treatment. A range of crosslinking was achieved by varying the radiation dose. In addition, low-temperature plasma treatment with hexamethyldisiloxane/O2 and C3F6 was investigated for comparison. The surface mechanical properties of the treated UHMWPE samples are compared with those of untreated UHMWPE samples used as controls. Surface adhesion measurements obtained from the nanoindentation material responses are also discussed in terms of important treatment parameters. Results demonstrate that high-dose oxygen ion implantation, argon ion beam treatment, and low-temperature C3F6 plasma modification are effective treatments for enhancing the surface mechanical properties of UHMWPE.

Two temperature regimes of triplet transfer in the dissociation of the correlated triplet pair after singlet fission

2019 ◽  
Vol 97 (6) ◽  
pp. 465-473 ◽  
Author(s):  
Tia S. Lee ◽  
YunHui L. Lin ◽  
Hwon Kim ◽  
Barry P. Rand ◽  
Gregory D. Scholes
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Temperature Regime ◽  
Transient Absorption Spectroscopy ◽  
Type Model ◽  
Singlet Fission ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Pair Separation ◽  
Triplet Pair

The ability to undergo spin-allowed exciton multiplication makes singlet fission materials promising for photovoltaic applications. Here, we examine the separation of correlated triplet pairs, 1(T…T), in polycrystalline pentacene films via temperature-dependent transient absorption spectroscopy. Single wavelength analysis reveals a profound delay in 1(T…T) dynamics. Moreover, the dynamics of 1(T…T) exhibit temperature dependence, whereas other features show no discernable temperature dependence. Previous literatures have suggested that correlated triplet separation is mediated by a thermally activated hopping process. Surprisingly, we found that the time constants governing triplet pair separation display two distinct temperature-dependent regimes of triplet transport. The high temperature regime follows a thermally activated hopping mechanism. The experimentally derived reorganization energy and electronic coupling is verified by density matrix renormalization group quantum chemical calculations. In addition, we evaluated the low temperature regime and show that the trend can be modelled by a Miller–Abrahams-type model that incorporates the effects of energetic disorder. We conclude that the correlated triplet pair separation is mediated by thermally activated hopping or a disorder driven Miller–Abrahams-type mechanism at high and low temperature, respectively. We observe that crossover between two regimes occurs ∼226 K. We find the time constant for triplet–triplet energy transfer to be 1.8 ps at ambient temperature and 21 ps at 77 K.

Hydrogen Passivation of Si Nanocrystals in Silica

2000 ◽  
Vol 650 ◽  
Author(s):  
Stephanie Cheylan ◽  
Robert G. Elliman
Keyword(s):  
Ion Implantation ◽  
Thermal Annealing ◽  
Silicon Nanocrystals ◽  
Emission Spectra ◽  
Red Shift ◽  
High Dose ◽  
Hydrogen Passivation ◽  
High Fluence ◽  
Si Nanocrystals ◽  
Pl Emission

ABSTRACTThis paper explores the effect of hydrogen on the luminescence properties of silicon nanocrystals formed in silica by high-dose ion-implantation and thermal annealing. For samples implanted to low fluence (small nanocrystals), passivation is shown to result in a uniform enhancement of the PL emission for all wavelengths. However, for samples implanted to high fluence, preferential enhancement of the emission from larger nanocrystals is evident, resulting in a red-shift of emission spectra. Both the intensity enhancement and the red-shift are shown to be reversible, with spectra returning to their pre-passivation form when H is removed from the samples by annealing. The luminescence lifetime is also shown to increase after passivation, confirming that defect-containing nanocrystals luminesce.

Analysis of Silicon-On-Insulator Structures Formed By Oxygen Ion Implantation

1985 ◽  
Vol 43 ◽  
pp. 300-301
Author(s):  
N. Lewis ◽  
E. L. Hall ◽  
A. Mogro-Campero ◽  
R. P. Love
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Dose ◽  
Crystal Silicon ◽  
Oxygen Ion ◽  
Oxygen Ion Implantation

The formation of buried oxide structures in single crystal silicon by high-dose oxygen ion implantation has received considerable attention recently for applications in advanced electronic device fabrication. This process is performed in a vacuum, and under the proper implantation conditions results in a silicon-on-insulator (SOI) structure with a top single crystal silicon layer on an amorphous silicon dioxide layer. The top Si layer has the same orientation as the silicon substrate. The quality of the outermost portion of the Si top layer is important in device fabrication since it either can be used directly to build devices, or epitaxial Si may be grown on this layer. Therefore, careful characterization of the results of the ion implantation process is essential.

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