• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.223-227
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• 1996

The effect of ZrC and VC addition on the diffusion induced recrystallization (DIR) of TiC-Cr3C2 has been investigated. With in creasing the amount of added ZrC to Cr3C2 the DIR of TiC was suppressed at the begining and then occurred. On the contrary the DIR was accelerated with the addition of VC to Cr3C2 Because the lattice parameters of (Ti, Cr)C and (Ti,V)C are smaller and that of (Ti, Zr)C is larger than that of TiC the lattice parameter of (Ti,Cr,Zr)C is expected to be similar to that of TiC,. The results indicate that the strain energy due to lattice mismatch between TiC and solid-solution carbide is the driving force of the observed energy due to lattice mismatch between TiC and solid-solution carbide is the driving force of the observed DIR.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.599-604
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• 2011

A highly strained nanostructure comprising crystallographically aligned HgTe nanoinclusions and a surrounding PbTe matrix has been synthesized using a precipitation process of supersaturated HgTe-PbTe alloys. From the early precipitation stage, HgTe nanoinclusions take disk shape, which is transformed from initial HgTe nuclei, although there is no lattice constant difference of the two end components at standard state. As a primary reason for the morphological transformation of the initial spherical HgTe nuclei to HgTe nanodisks, the induced lattice mismatch is suggested. On the condition that the HgTe nanodisks maintain perfect coherent nature with PbTe matrix, the stress-free lattice constant of constrained HgTe nanodisks has been calculated based on the defined concept of the strain-induced tetragonality, the linear elasticity and the actual measurement in HRTEM images.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.4
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• pp.172-175
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• 2003

We have investigated effects of the lattice mismatch between the LPE films and the substrates. We have grown $La_{2-x}Sr_{x}CuO_{4}$(x=0.1 to 0.15) single crystalline films on single crystalline substrates having different lattice parameter ratio c/a e.g., $La_{2-x}Sr_{x}Cu_{1-y}Zn_{y}O_{4},\;La_{2-x}Ba_{x}CuO_{4},\; LaSrAlO_{4}\;and\;La_{2-x}Sr_{x}Cu_{1-y}Al_{y}O_{4}$ etc., using the IR-LPE technique. The superconducting properties of the grown films were found to vary significantly depending on the lattice mismatch with different substrates.

• 전기의세계
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• v.28 no.4
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• pp.53-63
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• 1979

Interface recombination velocity in $Al_{x}$G $a_{1-x}$ As-GaAs and $Al_{0.85}$, G $a_{0.15}$ As-GaA $s_{1-y}$S $b_{y}$ heterojunction systems is studied as a function of lattice mismatch. The results are applied to the design of highly efficient III-V heterojunction solar cells. A horizontal liquid-phase epitaxial growth system was used to prepare p-p-p and p-p-n $Al_{x}$G $a_{1-x}$ As-GaA $s_{1-y}$S $b_{y}$-A $l_{x}$G $a_{1-x}$ As double heterojunction test samples with specified values of x and y. Samples were grown at each composition, with different GaAs and GaAs Sb layer thicknesses. A method was developed to obtain the lattice mismatch and lattice constants in mixed single crystals grown on (100) and (111)B oriented GaAs substrates. In the AlGaAs system, elastic lattice deformation with effective Poisson ratios .mu.$_{eff}$ (100=0.312 and .mu.$_{eff}$ (111B) =0.190 was observed. The lattice constant $a_{0}$ (A $l_{x}$G $a_{1-x}$ As)=5.6532+0.0084x.angs. was obtained at 300K which is in good Agreement with Vegard's law. In the GaAsSb system, although elastic lattice deformation was observed in (111) B-oriented crystals, misfit dislocations reduced the Poisson ratio to zero in (100)-oriented samples. When $a_{0}$ (GaSb)=6.0959 .angs. was assumed at 300K, both (100) and (111)B oriented GaAsSb layers deviated only slightly from Vegard's law. Both (100) and (111)B zero-mismatch $Al_{0.85}$ G $a_{0.15}$As-GaA $s_{1-y}$S $b_{y}$ layers were grown from melts with a weight ratio of $W_{sb}$ / $W_{Ga}$ =0.13 and a growth temperature of 840 to 820 .deg.C. The corresponding Sb compositions were y=0.015 and 0.024 on (100) and (111)B orientations, respectively. This occurs because of a fortuitous in the Sb distribution coefficient with orientation. Interface recombination velocity was estimated from the dependence of the effective minority carrier lifetime on double-heterojunction spacing, using either optical phase-shift or electroluminescence timedecay techniques. The recombination velocity at a (100) interface was reduced from (2 to 3)*10$^{4}$ for y=0 to (6 to 7)*10$^{3}$ cm/sec for lattice-matched $Al_{0.85}$G $a_{0.15}$As-GaA $s_{0.985}$S $b_{0.015}$ Although this reduction is slightly less than that expected from the exponential relationship between interface recombination velocity and lattice mismatch as found in the AlGaAs-GaAs system, solar cells constructed from such a combination of materials should have an excellent spectral response to photons with energies over the full range from 1.4 to 2.6 eV. Similar measurements on a (111) B oriented lattice-matched heterojunction produced some-what larger interface recombination velocities.ities.ities.s.

• Journal of the Korean institute of surface engineering
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• v.35 no.5
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• pp.289-294
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• 2002

ZnTe films have been grown on (100) GaAs substrate with two representative problems. The one is lattice mismatch, the other is thermal expansion coefficients mismatch of ZnTe /GaAs. It claims here, the relationship of film thickness and defects distribution with (100) ZnTe/GaAs using hot wall epitaxy (HWE) growth was investigated by transmission electron microscopy (TEM). It analyzed on the two-sort side using TEM with cross-sectional transmission electron microscopy (XTEM) and high-resolution electron microscopy (HREM). Investigation into the nature and behavior of dislocations with dependence-thickness in (100) ZnTe/ (100) GaAs hetero-structures grown by transmission electron microscopy (TEM). This defects range from interface to 0.7 $\mu\textrm{m}$ was high density, due to the large lattice mismatch and thermal expansion coefficients. The defects of low density was range 0.7$\mu\textrm{m}$~1.8$\mu\textrm{m}$. In the thicker range than 1.8$\mu\textrm{m}$ was measured hardly defects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.295-298
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• 1999

High quality of $Er_{2}O_{3}$ doped $LiNbO_{3}$ single crystal thin films were grown by the liquid phase epitaxial (LPE) method using $Er_{2}O_{3}$ doped at concentrations of 1,3, and 5 mol% respectively. After the growth of single crystal thin film, the crystallinity and the lattice mismatch along the c-axis between the film and the substrate was examined as a function of the variations of{{{{{Er}_{2}{O}_{3}}}}} dopant concentration using a X-ray double crystal technique. There was no lattice mismatch along the c-axis for the undoped film and those doped with 1 and 3 mol% of $Er_{2}O_{3}$. For 5 mol% of $Er_{2}O_{3}$ doped film, the lattice mismatch was $7.86{\times}10^{-4}$nm along the c-axis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.101-102
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• 2009

SGOI MOSFETs with various Ge mole fractions were fabricated and compared to the SOI MOSFET. SGOI MOSFETs have a lager drain current and higher effective mobility than the SOI MOSFET as increased Ge mole fractions. The lattice constant difference causes lattice mismatch between the SiGe layer and the top-Si layer during the top-Si layer growth. However, SGOI MOSFETs have a lager leakage current at subthreshold region. Also, leakage current at subthreshold region increased with Ge mole fractions. This is attributable to the crystalline defects due to the lattice mismatch between the SiGe layer and the top-Si layer.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.156-157
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• 1998

It is a diffcult and challenging pproblem to control the growth of eppitaxial films. Heteroeppitaxy is esppecially idfficult because of the lattice mismatch between sub-strate and depposited layers. This mismatch leads usually to a three dimensional(3D) island growth. But the use of surfactants such as As, Sb, and Bi can be beneficial in obtaining high quality heteroeppitaxial films. In this study medium energy ion scattering sppectroscoppy(MEIS) was used in order to reveal the growth mode of Ge on Si(001) and the strain of depposited film without and with dynamically supplied atomic hydrogen at the growth thempperature of 35$0^{\circ}C$. It was ppossible to control the growth mode from layer-by-layer followed by 3D island to layer-by-layer by controlling the hydrogen flux. In the absent of hydro-gen the film grows in the layer-by-layer mode within the critical thickness(about 3ML) and the 3D island formation is followed(Fig1). The 3D island formation is suppressed by introducing hydrogen resulting in layer-by-layer growth beyond the critical thickness(Fig2) We measured angular shift of blocking dipp in order to obtain the structural information on the thin films. In the ppressence of atomic hydrogen the blocking 야 is shifted toward higher scattering angle about 1。. That means the film is distorted tetragonally and strained therefore(Fig4) In other case the shift of blocking dipp at 3ML is almost same as pprevious case. But above the critical thickness the pposition of blocking dipp is similar to that of Si bulk(Fig3). It means the films is relaxed from the first layer. There is 4.2% lattice mismatch between Ge and Si. That mismatch results in about 2。 shift of blocking dipp. We measured about 1。 shift. This fact could be due to the intermixing of Ge and Si. This expperimental results are consistent with Vegard's law which says that the lattice constant of alloys is linear combination of the lattic constants of the ppure materials.

• Korean Journal of Materials Research
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• v.4 no.5
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• pp.516-523
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• 1994

The interfacial coherency of metal organic chemical vapor deposition grown InGaAsP/InP heterostructure wafers was examined and their influences on the optoelectronic properties were investigated in this study. (400) symmetric and (511) asymmetric reflections were employed to measure the lattice coherency. Existence of misfit dislocations was examined by x-ray topography and reverified by photoluminescence (PL) imaging. PI, measurements were performed, and higher PL intensity was obtained for elastically strained samples and lower intensity for plastically deformed samples. The highest PL intensity was obtained for the sample lattice matched at the growth temperature. PL full-width at half maximum (FWHM) was found to depend on the degree of lattice mismatch. A correlatior between x-ray FWHM and PL intensity was empirically established. The results presented demonstrate that the interfacial coherency is of primary significance in affecting the optoelectronic properties through elastic strain and plastic deformation.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.305-320
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• 1999

It was grown Er2O3 doped LiNbO3 single crystal thin films with high crystal quality by liquid phase epitaxial (LPE) method. Er2O3 was doped with a concentration of 1, 3, and 5 mol% respectively. After the growth of single crystal thin film, we examined the crystallinity and the lattice mismatch along the c-axis between the film and the substrate with the variation of Er2O3 dopant using X-ray double crystal technique. There were no lattice mismatches along the c-axis for the undoped and the films doped with 1 and 3 mol% of Er2O3. For 5 mol% of Er2O3 doped film, there was a lattice mismatch of 7.86x10-4nm along the c-axis.