Semiconductor Nanocrystals formed in SiO2 by Ion Implantation

1994 ◽  
Vol 358 ◽  
Author(s):  
Jane G. Zhu ◽  
C. W. White ◽  
J. D. Budai ◽  
S. P. Withrow ◽  
Y. Chen
Keyword(s):  
Ion Implantation ◽  
Annealing Temperature ◽  
Semiconductor Nanocrystals ◽  
Spherical Shape ◽  
Group Iv ◽  
Semiconductor Materials ◽  
Size Distributions ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Subsequent Thermal Annealing

ABSTRACTNanocrystals of group IV (Si, Ge and SiGe), III-V (GaAs), and II-VI (CdSe) semiconductor materials have been fabricated inside SiO2 by ion implantation and subsequent thermal annealing. The microstructure of these nanocrystalline semiconductor materials has been studied by transmission electron microscopy (TEM). The nanocrystals form in near-spherical shape with random crystal orientations in amorphous SiO2 Extensive studies on the nanocrystal size distributions have been carried out for the Ge nanocrystals by changing the implantation doses and the annealing temperatures. Remarkable roughening of the nanocrystals occurs when the annealing temperature is raised over the melting temperature of the implanted semiconductor material. Strong red photoluminescence peaked around 1.67 eV has been achieved in samples with Si nanocrystals in SiO2.

scholarly journals Ion Beam Synthesis Of Cds, ZnS, And PbS Compound Semiconductor Nanocrystals

1997 ◽  
Vol 504 ◽  
Author(s):  
C. W. White ◽  
J. D. Budai ◽  
A. L. Meldrum ◽  
S. P. Withrow ◽  
R. A. Zuhr ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Thermal Annealing ◽  
Ion Beam ◽  
Semiconductor Nanocrystals ◽  
Compound Semiconductor ◽  
Size Distributions ◽  
Pbs Nanocrystals ◽  
Ion Beam Synthesis ◽  
The Matrix

ABSTRACTSequential ion implantation followed by thermal annealing has been used to form encapsulated CdS, ZnS, and PbS nanocrystals in SiO2 and Al2O3 matrices. In SiO2, nanoparticles are nearly spherical and randomly oriented, and ZnS and PbS nanocrystals exhibit bimodal size distributions. In Al2O3, nanoparticles are facetted and oriented with respect to the matrix. Initial photoluminescence (PL) results are presented.

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

scholarly journals Near-IR Emitting Si Nanocrystals Fabricated by Thermal Annealing of SiNx/Si3N4 Multilayers

2019 ◽  
Vol 9 (22) ◽  
pp. 4725
Author(s):  
D. M. Zhigunov ◽  
A. A. Popov ◽  
Yu. M. Chesnokov ◽  
A. L. Vasiliev ◽  
A. M. Lebedev ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
X Ray ◽  
Near Ir ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Mean Size ◽  
The One ◽  
Multilayered Thin Films

Silicon nanocrystals in silicon nitride matrix are fabricated by thermal annealing of SiNx/Si3N4 multilayered thin films, and characterized by transmission electron microscopy, X-ray reflectivity and diffraction analysis, photoluminescence and X-ray photoelectron spectroscopy techniques. Si nanocrystals with a mean size of about 4 nm are obtained, and their properties are studied as a function of SiNx layer thickness (1.6–2 nm) and annealing temperature (900–1250 °C). The effect of coalescence of adjacent nanocrystals throughout the Si3N4 barrier layers is observed, which results in formation of distinct ellipsoidal-shaped nanocrystals. Complete intermixing of multilayered film accompanied by an increase of nanocrystal mean size for annealing temperature as high as 1250 °C is shown. Near-IR photoluminescence with the peak at around 1.3–1.4 eV is detected and associated with quantum confined excitons in Si nanocrystals: Photoluminescence maximum is red shifted upon an increase of nanocrystal mean size, while the measured decay time is of order of microsecond. The position of photoluminescence peak as compared to the one for Si nanocrystals in SiO2 matrix is discussed.

TEM study of CdS nanocrystals formed in SiO2 by ion implantation

1996 ◽  
Vol 54 ◽  
pp. 236-237
Author(s):  
Jane G. Zhu ◽  
C. W. White ◽  
J. D. Budai ◽  
S. P. Withrow
Keyword(s):  
Ion Implantation ◽  
Electronic Device ◽  
Semiconductor Nanocrystals ◽  
Optical Nonlinearity ◽  
Silicon Substrates ◽  
Cds Nanocrystals ◽  
Quantum Confinement Effects ◽  
Transmission Electron ◽  
Device Applications ◽  
Ion Profiles

Quantum confinement effects and enhanced optical nonlinearity are expected from II-VI semiconductor nanocrystals, which are important for novel opto-electronic device applications. The ion implantation method has been used in our study to form CdS nanocrystals inside amorphous SiO2. The CdS nanocrystals were studied by transmission electron microscopy (TEM).The samples were implanted (at room temperature) with equal doses (1×1017 ions/cm2) of Cd and S into a SiO2 layer on (100) silicon substrates and then annealed under Ar + 4%H2 ambient at 800°C and 1000°C for 1 h. Implant energies were chosen to overlap the Cd and S ion profiles in the middle of the oxide layer. CdS precipitates are formed during the thermal annealing.The effect of annealing temperatures on the nanocrystals size distributions are revealed in Figs. 1 and 2. The sizes of CdS nanocrystals are in the range of 2 - 11 nm for the sample annealed at 800°C, and in the range of a few to 16 nm for the sample annealed at 1000°C.

Microstructure and Size Distribution of Compound Semiconductor Nanocrystals Synthesized by Ion Implantation

1998 ◽  
Vol 536 ◽  
Author(s):  
A. Meldrum ◽  
S. P. Withrow ◽  
R. A. Zuhr ◽  
C. W. White ◽  
L. A. Boatnerl ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Semiconductor Nanocrystals ◽  
Compound Semiconductor ◽  
Fused Silica ◽  
Silica Matrix ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Host Materials ◽  
Device Applications ◽  
Versatile Technique

AbstractIon implantation is a versatile technique by which compound semiconductor nanocrystals may be synthesized in a wide variety of host materials. The component elements that form the compound of interest are implanted sequentially into the host, and nanocrystalline precipitates then form during thermal annealing. Using this technique, we have synthesized compound semiconductor nanocrystal precipitates of ZnS, CdS, PbS, and CdSe in a fused silica matrix. The resulting microstructures and size distributions were investigated by cross-sectional transmission electron microscopy. Several unusual microstructures were observed, including a band of relatively large nanocrystals at the end of the implant profile for ZnS and CdSe, polycrystalline agglomerates of a new phase such as γ-Zn 2SiO4, and the formation of central voids inside CdS nanocrystals. While each of these microstructures is of fundamental interest, such structures are generally not desirable for potential device applications for which a uniform, monodispersed array of nanocrystals is required. Methods were investigated by which these unusual microstructures could be eliminated.

scholarly journals Oxidation of Si nanocrystals fabricated by ultra-low energy ion implantation in thin SiO2 layers

2004 ◽  
Vol 830 ◽  
Author(s):  
H. Coffin ◽  
C. Bonafos ◽  
S. Schamm ◽  
N. Cherkashin ◽  
M. Respaud ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Structural Characteristics ◽  
Scanning Transmission Electron Microscope ◽  
Chemical Oxidation ◽  
Low Energy ◽  
Annealing Duration ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Scanning Transmission

ABSTRACTThe effect of annealing in diluted oxygen on the structural characteristics of thin silicon dioxide layers with embedded Si nanocrystals fabricated by ultra-low energy ion implantation (1 keV) is reported. The nanocrystal characteristics (size, density, coverage) have been measured by spatially resolved Electron Energy Loss Spectroscopy using the spectrum-imaging mode of a Scanning Transmission Electron Microscope. Their evolution has been studied as a function of the annealing duration under N2+O2 at 900°C. An extended spherical Deal-Grove model for the self-limiting oxidation of embedded silicon nanocrystals has been carried out. It shows that stress effects, due to the deformation of the oxide, slows down the chemical oxidation rate and leads to a self-limiting oxide growth. The model predictions show a good agreement with the experimental results.

Bimodal Microstructures in Nanocrystalline Al and Al-Mg Alloy Powders Prepared by Cryogenic Ball Milling

2004 ◽  
Vol 821 ◽  
Author(s):  
F. Zhou ◽  
Z. Lee ◽  
E. J. Lavernia ◽  
S.R. Nutt
Keyword(s):  
Electron Microscopy ◽  
Ball Milling ◽  
Elevated Temperatures ◽  
Mg Alloy ◽  
Size Distributions ◽  
Transmission Electron ◽  
Grain Size Distributions ◽  
Equiaxed Grains ◽  
Bimodal Grain Size ◽  
Subsequent Thermal Annealing

AbstractThe microstructures of nanocrystalline Al and Al-7.6 at% Mg alloy powders processed by cryogenic ball milling (i.e., cryomilling) and subsequent thermal annealing were characterized using transmission electron microscopy. The as-milled samples primarily consisted of equiaxed grains with average sizes of ∼ 26 nm. The annealing treatments at elevated temperatures resulted in bimodal grain-size distributions, with sub-micrometer-sized grains embedded in a matrix of nanocrystalline (<50 nm) grains. The bimodal microstructures were formed during the processes of recovery and recrystallization.

Annealing Temperature Effect on the Photoluminescence Properties of Er-Doped Silicon-Rich Silicon Oxide Films

2013 ◽  
Vol 721 ◽  
pp. 16-19
Author(s):  
Chang Qing Li ◽  
Pei Jia Liu ◽  
Yong Mei Wang ◽  
K. Murakami
Keyword(s):  
Annealing Temperature ◽  
Silicon Oxide ◽  
Photoluminescence Properties ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Large Particles ◽  
Different Temperatures ◽  
Pl Intensity ◽  
Er Doped ◽  
The Relationship

Er-dispersed silicon-rich silicon oxide (SRSO:Er) films have been fabricated by pulsed laser ablation technique. After deposition, the films were annealed in Ar ambient at different temperatures for 30 min to generate SiO2films containing Si nanocrystals (Si-nc) and Er ions. The relationship between Er photoluminescence (PL) intensity and annealing temperature was investigated by PL spectrums analysis at room temperature. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectrometer (EDS) were used to observe the samples. Experimental results show that high-density Si-nc generate when the annealing temperature increases to 1000°C, however, PL intensity of Er decreases due to Er atoms segregated out in SiO2film and formed large particles.

scholarly journals Improving Passivation Process of Si Nanocrystals Embedded in SiO2Using Metal Ion Implantation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jhovani Bornacelli ◽  
Jorge Alejandro Reyes Esqueda ◽  
Luis Rodríguez Fernández ◽  
Alicia Oliver
Keyword(s):  
Ion Implantation ◽  
Metal Ion ◽  
Surface Defects ◽  
Time Resolved ◽  
Noticeable Increase ◽  
Passivation Process ◽  
Si Nanocrystals ◽  
Subsequent Thermal Annealing ◽  
High Depth ◽  
Metal Ion Implantation

We studied the photoluminescence (PL) of Si nanocrystals (Si-NCs) embedded in SiO2obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm) inside the SiO2achieving a robust and better protected system. After metal ion implantation (Ag or Au), and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs) could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2and Ar) to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

XTEM study of phase transition in MeV ion-implanted InP

1988 ◽  
Vol 46 ◽  
pp. 796-797
Author(s):  
Fulin Xiong
Keyword(s):  
Phase Transition ◽  
Ion Implantation ◽  
Structural Changes ◽  
Ion Irradiation ◽  
Device Fabrication ◽  
Cross Sectional ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Post Implantation ◽  
Subsequent Thermal Annealing

MeV ion implantation into III-V compound semiconductors has attracted great attention in recent years because of its high potential for 3-dimensional device fabrication technology. However, a thorough understanding of associated physical processes involved is crucial before it can be universally applied. Our study on this subject with InP using cross sectional and high resolution transmission electron microscopy (XTEM, HRTEM) reveals clearly the structural changes occurring during MeV-ion-implantation and subsequent thermal annealing. It has lead to a better understanding of the mechanism of phase transition in InP under MeV ion irradiation.Samples of n-type InP(lOO) single crystalline wafers were implanted with 5 MeV-N-ions in room temperature with doses ranging from 1014 to 1016/cm2. Post-implantation annealing was carried out in a graphite strip heater at 500 C with ambient H2 flow.Fig. 1 shows a typical XTEM view of an implanted sample at a dose of 1 x 1016/cm2. A wide implanted layer is buried at a maximum depth of 4μm with a slightly damaged top surface. The buried layer appears as a highly disordered crystalline structure when the sample was annealed, whereas it is amorphous in an as-implanted sample.

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