EQUALLY STRAINED Si/SiGe SUPERLATTICES ON Si SUBSTRATES

1985 ◽  
Vol 56 ◽  
Author(s):  
E. KASPER ◽  
H.-J. HERZOG ◽  
H.DAEMBKES-a1 ◽  
G. ABSTREITER
Keyword(s):  
Molecular Beam Epitaxy ◽  
Room Temperature ◽  
Molecular Beam ◽  
Electron Gas ◽  
Phonon Modes ◽  
Strained Si ◽  
Si Substrates ◽  
Device Applications ◽  
Strained Layer Superlattices ◽  
Material Concept

AbstractGrowth of Si/SiGe superlattices on Si substrates by molecular beam epitaxy (MBE) is described. Strain symmetrization in the superlattice is achieved with an incommensurate SiGe buffer layer. The concept of strainsymmetrization is explained and properties of buffer and strained layer superlattices are investigated. A twodimensional electron gas with enhanced room temperature mobility and folded phonon modes within the reduced onedimensional Brillouin zone are observed. An n-channel Si/SiGe MODFET demonstrates the device applications of this material concept.

Comparison of the Optical Properties of Er3+ Doped Gallium Nitride Prepared by Metalorganic Molecular Beam Epitaxy (MOMBE) and Solid Source Molecular Beam Epitaxy (SSMBE)

1999 ◽  
Vol 595 ◽  
Author(s):  
U. Hömmerich ◽  
J. T. Seo ◽  
J. D. MacKenzie ◽  
C. R. Abernathy ◽  
R. Birkhahn ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Excited States ◽  
Room Temperature ◽  
Molecular Beam ◽  
Average Lifetime ◽  
Green Luminescence ◽  
Si Substrates ◽  
Lifetime Analysis ◽  
Metalorganic Molecular Beam Epitaxy ◽  
Er Doped

AbstractWe report on the luminescence properties of Er doped GaN grown prepared by metalorganic molecular beam epitaxy (MOMBE) and solid-source molecular beam epitaxy (SSMBE) on Si substrates. Both types of samples emitted characteristic 1.54 µm PL resulting from the intra-4f Er3+ transition 4I13/2→4I15/2. Under below-gap excitation the samples exhibited very similar 1.54 µm PL intensities. On the contrary, under above-gap excitation GaN: Er (SSMBE) showed ∼80 times more intense 1.54 µm PL than GaN: Er (MOMBE). In addition, GaN: Er (SSMBE) also emitted intense green luminescence at 537 nm and 558 nm, which was not observed from GaN: Er (MOMBE). The average lifetime of the green PL was determined to be 10.8 µs at 15 K and 5.5 µs at room temperature. A preliminary lifetime analysis suggests that the decrease in lifetime is mainly due to the strong thermalization between the 2H11/2 and 4S3/2 excited states. Nonradiative decay processes are expected to only weakly affect the green luminescence.

scholarly journals Comparison of the Optical Properties of Er3+ Doped Gallium Nitride Prepared by Metalorganic Molecular Beam Epitaxy (Mombe) and Solid Source Molecular Beam Epitaxy (SSMBE)

2000 ◽  
Vol 5 (S1) ◽  
pp. 824-830 ◽  
Author(s):  
U. Hömmerich ◽  
J. T. Seo ◽  
J. D. MacKenzie ◽  
C. R. Abernathy ◽  
R. Birkhahn ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Excited States ◽  
Room Temperature ◽  
Molecular Beam ◽  
Average Lifetime ◽  
Green Luminescence ◽  
Si Substrates ◽  
Lifetime Analysis ◽  
Metalorganic Molecular Beam Epitaxy ◽  
Er Doped

We report on the luminescence properties of Er doped GaN grown prepared by metalorganic molecular beam epitaxy (MOMBE) and solid-source molecular beam epitaxy (SSMBE) on Si substrates. Both types of samples emitted characteristic 1.54 µm PL resulting from the intra-4f Er3+ transition 4I13/2→4I15/2. Under below-gap excitation the samples exhibited very similar 1.54 µm PL intensities. On the contrary, under above-gap excitation GaN: Er (SSMBE) showed ∼80 times more intense 1.54 µm PL than GaN: Er (MOMBE). In addition, GaN: Er (SSMBE) also emitted intense green luminescence at 537 nm and 558 nm, which was not observed from GaN: Er (MOMBE). The average lifetime of the green PL was determined to be 10.8 µs at 15 K and 5.5 µs at room temperature. A preliminary lifetime analysis suggests that the decrease in lifetime is mainly due to the strong thermalization between the 2H11/2 and 4S3/2 excited states. Nonradiative decay processes are expected to only weakly affect the green luminescence.

GexSi1-x/Si superlattices grown on (100)-, (111)-, and (110)-oriented Si substrates

1989 ◽  
Vol 47 ◽  
pp. 580-581
Author(s):  
T. S. Kuan ◽  
S. S. Iyer ◽  
E. M. Yeo
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Long Range Order ◽  
Defect Structures ◽  
Si Substrate ◽  
Growth Morphology ◽  
Si Substrates ◽  
Device Applications ◽  
20 Nm

GexSi1-x/Si heterostructures have been studied extensively because of their potential device applications. Previous GexSi1-x/Si heteroepitaxy studies have been mostly confined to growth on (100) surfaces and have focused on how growth temperature and GexSi1-x layer thickness affect growth morphology and defect generation. In this work we compare the quality of GexSi1-x/Si superlattices grown on (100)-, (111)-, and (110)-oriented Si substrates. We find that these three growth directions give rise to different growth morphologies and defect structures. Strained GexSi1-x layers in a (100) GexSi1-x/Si superlattice annealed at 450 – 500°C have recently been reported to exhibit a CuPt-type long-range order. Thus, another objective of this work is to explore whether growth along the <110> and/or <111> directions can promote or suppress the onset of ordering.Superlattices consisting of 18 layers of alternating Ge0.5Si0.5 (5 nm) and Si (20 nm) were grown by molecular beam epitaxy (MBE). Before growing the superlattice, a 3D-nm-thick Si buffer layer was grown on the Si substrate.

Arsenic diffusion in Si and Si0.9Ge0.1 alloys: Effect of defect injection

2004 ◽  
Vol 809 ◽  
Author(s):  
Suresh Uppal ◽  
J. M. Bonar ◽  
Jing Zhang ◽  
A. F. W. Willoughby
Keyword(s):  
Molecular Beam Epitaxy ◽  
Rapid Thermal Annealing ◽  
Enhancement Factor ◽  
Molecular Beam ◽  
Strained Si ◽  
Vacancy Defects ◽  
Si Substrates ◽  
Defect Injection ◽  
Diffusion Enhancement

ABSTRACTResults of intrinsic As diffusion in Si as well as in strained and relaxed Si0.9Ge0.1 layers are presented. Using Molecular Beam Epitaxy in-situ As doped epitaxial Si and compressively strained and relaxed Si-Ge layers were grown on Si substrates. The samples were annealed using Rapid Thermal Annealing (RTA) at 1000 °C. Arsenic diffusion is seen to be enhanced in SiGe than in Si. The enhancement factor is calculated to be 2.3 and 1.3 for relaxed and strained Si0.9Ge0.1, respectively. Also, using RTA in oxygen atmosphere, interstitial and vacancies were selectively injected in to the sample structures. Diffusion enhancement is also recorded in Si and Si-Ge structures with interstitial as well as vacancy injections over inert anneal. The results suggest that both interstitial and vacancy defects contribute to As diffusion in Si and Si0.9Ge0.1.

Heteroepitaxy on Silicon by Molecular Beam Epitaxy

1988 ◽  
Vol 116 ◽  
Author(s):  
Leo J. Schowalter
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Three Dimensional ◽  
In Situ Observation ◽  
Free Energies ◽  
Practical Applications ◽  
Si Substrates ◽  
Ballistic Electron ◽  
Device Applications ◽  
Heteroepitaxial Layers

AbstractIn recent years extensive research has been conducted on growing heteroepitaxial layers of insulators, metals, and other semiconductors on silicon. This work promises to extend the use of Si (or, at least, Si substrates) far beyond present day devices into hybred semiconductor devices, optoelectronics, ballistic electron devices, and three-dimensional device structures. However, the “art” of heteroepitaxy is still poorly understood and much work remains to be done to realize most practical applications. Molecular beam epitaxy (MBE) represents an attractive technique for research and development of heteroepitaxy because of its relatively low growth temperatures, flexibility in working with different materials, and by providing a good environment for in-situ observation of the heteroepitaxial process. Using examples from recent heteroepitaxial work by molecular beam epitaxy in the areas of CaF2, NiSi2 and CoSi2, and GaAs on Si, this paper discusses how heteroepitaxial quality is affected by the relative surface free energies and strain (due to both lattice and thermal expansion coefficient mismatch). The goal is to produce better heteroepitaxial layers for device applications by an improved understanding of the process.

Room-temperature ferromagnetism in (Mn, N)-codoped TiO2 films grown by plasma assisted molecular beam epitaxy

2008 ◽  
Vol 104 (9) ◽  
pp. 093914 ◽  
Author(s):  
X. Y. Li ◽  
S. X. Wu ◽  
L. M. Xu ◽  
Y. J. Liu ◽  
X. J. Xing ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Room Temperature ◽  
Molecular Beam ◽  
Room Temperature Ferromagnetism ◽  
Tio2 Films ◽  
Codoped Tio2

Room-Temperature Wafer Bonded Multi-Junction Solar Cell Grown by Solid State Molecular Beam Epitaxy

MRS Advances ◽  
2016 ◽  
Vol 1 (43) ◽  
pp. 2907-2916 ◽  
Author(s):  
Shulong Lu ◽  
Shiro Uchida
Keyword(s):  
Solar Cell ◽  
Molecular Beam Epitaxy ◽  
Wafer Bonding ◽  
Room Temperature ◽  
Molecular Beam ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Device Structure ◽  
Junction Solar Cell

ABSTRACTWe studied the InGaP/GaAs//InGaAsP/InGaAs four-junction solar cells grown by molecular beam epitaxy (MBE), which were fabricated by the novel wafer bonding. In order to reach a higher conversion efficiency at highly concentrated illumination, heat generation should be minimized. We have improved the device structure to reduce the thermal and electrical resistances. Especially, the bond resistance was reduced to be the lowest value of 2.5 × 10-5 Ohm cm2 ever reported for a GaAs/InP wafer bond, which was obtained by the specific combination of p+-GaAs/n-InP bonding and by using room-temperature wafer bonding. Furthermore, in order to increase the short circuit current density (Jsc) of 4-junction solar cell, we have developed the quality of InGaAsP material by increasing the growth temperature from 490 °C to 510 °C, which leads to a current matching. In a result, an efficiency of 42 % at 230 suns of the four-junction solar cell fabricated by room-temperature wafer bonding was achieved.

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