Ion Beam Synthesis of Luminescent SI and GE Nanocrystals in a Silicon Dioxide Matrix

1993 ◽  
Vol 316 ◽  
Author(s):  
H.A. Atwater ◽  
K.V. Shcheglov ◽  
S.S. Wong ◽  
K.J. Vahala ◽  
R.C. Flagan ◽  
...  
Keyword(s):  
Ion Beam ◽  
Optoelectronic Device ◽  
Structural Defects ◽  
Si Substrates ◽  
Localized State ◽  
Transmission Electron ◽  
Ion Beam Synthesis ◽  
Theoretical Predictions ◽  
Device Applications ◽  
Ge Nanocrystals

ABSTRACTIon beam synthesis of Si and Ge nanocrystals in an SiO2 matrix is performed by precipitation from supersaturated solid solutions created by ion implantation. Films of SiO2 on (100) Si substrates are implanted with Si and Ge at doses 1 × 1016/cm2 - 5 × 1016/cm2. Implanted samples are subsequently annealed to induce precipitation of Si and Ge nanocrystals. Raman spectroscopy and high-resolution transmission electron microscopy indicate a correlation between visible room-temperature photoluminescence and the formation of diamond cubic nanocrystals approximately 2–5 nm in diameter in annealed samples. As-implanted but unannealed samples do not exhibit luminescence. Rutherford backscattering spectra indicate a steepening of implanted Ge profiles upon annealing. Photoluminescence spectra are correlated with annealing temperatures, and compared with theoretical predictions for various possible luminescence mechanisms, such as radiative recombination of quantum-confined excitons, as well as possible localized state luminescence related to structural defects in SiO2. Potential optoelectronic device applications are also discussed.

Ion Beam Synthesis of Luminescent Si and Ge Nanocrystals in a Silicon Dioxide Matrix

1993 ◽  
Vol 321 ◽  
Author(s):  
H. A. Atwater ◽  
K. V. Shcheglov ◽  
S. S. Wong ◽  
K. J. Vahala ◽  
R. C. Flagan ◽  
...  
Keyword(s):  
Ion Beam ◽  
Optoelectronic Device ◽  
Structural Defects ◽  
Si Substrates ◽  
Localized State ◽  
Transmission Electron ◽  
Ion Beam Synthesis ◽  
Theoretical Predictions ◽  
Device Applications ◽  
Ge Nanocrystals

ABSTRACTIon beam synthesis of Si and Ge nanocrystals in an SiO2 Matrix is performed by precipitation from supersaturated solid solutions created by ion implantation. Films of SiO2 on (100) Si substrates are implanted with Si and Ge at doses 1 × 1016/cm2 - 5 × 1016/cm2. IMplanted samples are subsequently annealed to induce precipitation of Si and Ge nanocrystals. Raman spectroscopy and high-resolution transmission electron microscopy indicate a correlation between visible room-temperature photoluminescence and the formation of diamond cubic nanocrystals approximately 2–5 nm in diameter in annealed samples. As-implanted but unannealed samples do not exhibit luminescence. Rutherford backscattering spectra indicate a steepening of implanted Ge profiles upon annealing. Photoluminescence spectra are correlated with annealing temperatures, and compared with theoretical predictions for various possible luminescence Mechanisms, such as radiative recombination of quantum-confined excitons, as well as possible localized state luminescence related to structural defects in SiO2 Potential optoelectronic device applications are also discussed.

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

Characterization and Manipulation of Exposed Ge Nanocrystals

2004 ◽  
Vol 818 ◽  
Author(s):  
I.D. Sharp ◽  
Q. Xu ◽  
C.Y. Liao ◽  
D.O. Yi ◽  
J.W. Ager ◽  
...  
Keyword(s):  
Hydrofluoric Acid ◽  
Metal Films ◽  
Silica Matrix ◽  
Size Distributions ◽  
Si Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Oxide Matrix ◽  
Ge Nanocrystals

AbstractIsotopically pure 70Ge and 74Ge nanocrystals embedded in SiO2 thin films on Si substrates have been fabricated through ion implantation and thermal annealing. Nanocrystals were subsequently exposed using a hydrofluoric acid etching procedure to selectively remove the oxide matrix while retaining up to 69% of the implanted Ge. Comparison of transmission electron micrographs (TEM) of as-grown crystals to atomic force microscope (AFM) data of exposed crystals reveals that the nanocrystal size distribution is very nearly preserved during etching. Therefore, this process provides a new means to use AFM for rapid and straightforward determination of size distributions of nanocrystals formed in a silica matrix. Once exposed, nanocrystals may be transferred to a variety of substrates, such as conducting metal films and optically transparent insulators for further characterization.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

Residue-Free Suspended Graphene Transferred by Perforated Template

2021 ◽  
Author(s):  
sangmin kim ◽  
Choong-Kwang Lee ◽  
Sung-Uk Yoon ◽  
Kyung-Shik Kim ◽  
Yun Hwangbo
Keyword(s):  
2D Materials ◽  
Si Substrates ◽  
Polymer Templates ◽  
Transmission Electron ◽  
Powerful Approach ◽  
Device Applications ◽  
Thermal Annealing Process ◽  
Specific Position ◽  
Transfer Method ◽  
Subsequent Thermal Annealing

Abstract A residue-free transfer method for graphene is proposed in this study, especially for the fabrication of suspended structures. Using perforated polymer templates, graphene can be precisely transferred onto the specific position in the perforated target SiO2/Si substrates without the need for polymer removal and the subsequent thermal annealing process. The surface of the transferred graphene by the proposed method was analyzed and corroborated via Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy. The results of these analyses suggest that the graphene surface has no polymeric residues resulting from the transfer process. The proposed method provides a powerful approach for the transfer of 2D materials and it enables the exploitation of their suspended structures for device applications as well as the physical characterizations without worry on the effect of contaminants.

Formation of Excess Donors During High-Dose 74Ge+ Ion Implantation

1994 ◽  
Vol 354 ◽  
Author(s):  
Z. Xia ◽  
E. Ristolainen ◽  
R. Elliman ◽  
H. Ronkainen ◽  
S. Eränen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Defects ◽  
High Dose ◽  
Donor Concentration ◽  
Materials Analysis ◽  
Si Substrates ◽  
Transmission Electron ◽  
Activation Annealing ◽  
Secondary Ion

AbstractRecently observations that high-dose Ge implantations into Si substrates caused the n-type carrier concentration to increase were attributed to residual structural defects after activation annealing [7,12]. However, co-implantation of an n-type impurity is another possibility. The origin of this excess donor concentration has been studied in this work. The possibilities of residual defects versus implantation of impurities have been investigated using two different implanters and materials analysis. Comparison of data from different implanters showed that the concentration of excess donors was sensitive to the implanter configuration. Furthermore, transmission electron microscopy (TEM), Rutherford backscattering channeling (RBS-C), and spreading resistance profiling (SRP) data showed that the excess donor effect was related to impurities rather than residual defects. Secondary-ion mass spectroscopy (SIMS) and SRP measurements confirmed that impurities such as 75As ions were present after implants. This impurity easily explains the excess donor concentration when 75Ge implants are performed into silicon wafers doped with phosphorous.

Formation of Sub-100 NM GE Wires on Si by E-Beam Evaporation/Lithography

1995 ◽  
Vol 380 ◽  
Author(s):  
C. Deng ◽  
J. C. Wu ◽  
C. J. Barbero ◽  
T. W. Sigmon ◽  
M. N. Wybourne
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Si Substrates ◽  
Novel Technique ◽  
Atomic Force ◽  
Transmission Electron ◽  
First Time ◽  
Scanning Electron

ABSTRACTA fabrication process for sub-100 nm Ge wires on Si substrates is reported for the first time. Wires with a cross section of 6 × 57 nm2 are demonstrated. The wire structures are analyzed by atomic force (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Sample preparation for TEM is performed using a novel technique using both pre and in situ deposition of multiple protection layers using a Focused Ion Beam (FIB) micromachining system.

Ion Beam Synthesis of Buried CoxNi1−xSi2 Layers in Silicon

1993 ◽  
Vol 320 ◽  
Author(s):  
M.F. Wu ◽  
J. De Wachter ◽  
A.-M. Van Bavel ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Ion Beam ◽  
Type A ◽  
Type B ◽  
X Ray Diffraction ◽  
Silicide Layer ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Unique Distribution ◽  
Buried Layers

ABSTRACTHeteroepitaxial CoxNi1−xSi2 layers with good crystalline quality have been formed by ion beam synthesis. Rutherford Backscattering (RBS) - Channeling, Auger Electron Spectroscopy (AES), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) have been used to study the buried layers. For a sample with x=0.66, we found that this ternary silicide layer contains 11% type B and 89% type A orientation. The TEM investigation reveals that the type B component is mainly located at the interfaces with a thickness of a few monolayers. XRD studies show that the strain of the type B component is smaller than that of the type A component, and this is probably the reason for such a unique distribution of the type B component in the epilayer.

scholarly journals Luminescence Properties of Si Nanocrystals Fabricated by Ion Beam Sputtering and Annealing

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sung Kim ◽  
Dong Hee Shin ◽  
Dong Yeol Shin ◽  
Chang Oh Kim ◽  
Jae Hee Park ◽  
...  
Keyword(s):  
Recent Progress ◽  
Ion Beam ◽  
Single Layer ◽  
Optoelectronic Device ◽  
Ion Beam Sputtering ◽  
Sputtering Deposition ◽  
The Past ◽  
Si Nanocrystals ◽  
Beam Sputtering ◽  
Device Applications

During the past several decades, Si nanocrystals (NCs) have received remarkable attention in view of potential optoelectronic device applications. This paper summarizes recent progress in the study of luminescence from Si NCs, such as photoluminescence (PL), cathodoluminescence, time-solved PL, and electroluminescence. The paper is especially focused on Si NCs produced by ion beam sputtering deposition ofSiOxsingle layer orSiOx/SiO2multilayers and subsequent annealing. The effects of stoichiometry (x) and thickness of SiOxlayers on the luminescence are analyzed in detail and discussed based on possible mechanisms.

Fabrication of PZT Based Capacitor with SrRuO3 Electrode for Memory Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
Ashok Kumar ◽  
H. Rahman ◽  
M. Shamsuzzoha
Keyword(s):  
Ferroelectric Properties ◽  
Ruthenium Oxide ◽  
Memory Device ◽  
Ferroelectric Material ◽  
Test System ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Device Applications

AbstractStrontium ruthenium oxide (SrRuO3) was deposited on Pt/(100)Si substrates at varying temperatures and 300 mTorr oxygen pressure using the pulsed laser deposition method and was found to be highly crystalline and textured when deposited over 450°C. After achieving highly crystalline SrRuO3 films, capacitors using the ferroelectric material - PZT (PbZr0.5Ti0.48O3) were successfully fabricated on Pt/(100)Si substrates. The ferroelectric properties of the films were determined by the RT66A Standardized Ferroelectric Test System. The structural properties of the films were analyzed by X-ray diffraction. Transmission electron microscopy was used to determine the crystallinity and quality of interfaces among different layers.

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