Modified surface states of NaGdF4:Yb3+/Tm3+ up-conversion nanoparticles via a post-chemical annealing process

Nanoscale ◽  
2018 ◽  
Vol 10 (40) ◽  
pp. 19031-19038 ◽  
Author(s):  
Qiuhong Min ◽  
Lei Zhao ◽  
Yushuang Qi ◽  
Jing Lei ◽  
Wenbo Chen ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Surface States ◽  
Amorphous Layer ◽  
Annealing Process ◽  
Chemical Annealing ◽  
Modified Surface

An amorphous layer acting as a quenching center at the surface of oleic acid-capped NaGdF4:Yb3+/Tm3+ nanoparticles is observed directly, which can be reconstructed via a novel post-chemical annealing process.

Characterization of Molecular Modified Surface States by Wavelength- and Time-Dependent Two-Photon Photoemission Spectroscopy

1997 ◽  
Vol 101 (20) ◽  
pp. 4085-4089 ◽  
Author(s):  
A. Kadyshevitch ◽  
R. Naaman ◽  
R. Cohen ◽  
D. Cahen ◽  
J. Libman ◽  
...  
Keyword(s):  
Surface States ◽  
Time Dependent ◽  
Photoemission Spectroscopy ◽  
Two Photon ◽  
Modified Surface

Low Temperature Annealing of Arsenic Implanted Silicon

1977 ◽  
Vol 35 ◽  
pp. 44-45
Author(s):  
V. C. Kannan
Keyword(s):  
Integrated Circuits ◽  
Annealing Temperature ◽  
Amorphous Layer ◽  
Annealing Process ◽  
Dislocation Loops ◽  
Junction Depth ◽  
Left Behind ◽  
Low Temperature Annealing ◽  
History Of ◽  
Rate Of Heating

When arsenic ions are implanted into silicon to a dose of 2xl014 ions/ cm2 or higher, the implanted surface becomes amorphous. The amorphous layer epitaxially recrystallizes back to the original substrate orientation upon annealing at or above 500°C. In the manufacture of integrated circuits and other devices, annealing is carried out at about 900°C in order to restore the electrical activity of implanted arsenic and also to obtain suitable junction depth (drive-in process). The annealing process is, however, not perfect and depending upon annealing temperature and time, interstitial dislocation loops and other unresolvable defects are left behind at the end of the annealing process. The formation of defects is also critically dependent upon the processing variables, namely, the rate of heating to the annealing temperature and the previous thermal history of the sample. Using channelling experiments, Csepregi et.al.

scholarly journals Surface reconstructions and modified surface states in La1−xCaxMnO3

2018 ◽  
Vol 2 (10) ◽  
Author(s):  
Rama K. Vasudevan ◽  
Hemant Dixit ◽  
Alexander Tselev ◽  
Liang Qiao ◽  
Tricia L. Meyer ◽  
...  
Keyword(s):  
Surface States ◽  
Surface Reconstructions ◽  
Modified Surface

scholarly journals INVESTIGATION OF PASSIVATION OF SURFACE STATES OF SINGLE CRYSTALLINE SILICON IN HETEROSTRUCTURES WITH AN INTEGRATED THIN AMORPHOUS LAYER

2020 ◽  
Vol 5 (333) ◽  
pp. 95-101
Author(s):  
N.А. Chuchvaga ◽  
◽  
А.V. Semenov ◽  
А.S. Titov ◽  
N.S. Tokmoldin ◽  
...  
Keyword(s):  
Solar Cell ◽  
Amorphous Silicon ◽  
Silicon Substrate ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Surface States ◽  
Amorphous Layer ◽  
Charge Carriers ◽  
Equilibrium Charge ◽  
Resistance Structure

This work presented in this publication is a continuation of works [1] and [2]. We have shown that in solar cells of the HIT structure, when the thickness of the embedded amorphous layer increases, the efficiency of the solar cell increases, but to a certain point of maximum. The increase in characteristics is due to an increase in the lifetime of non-basic charge carriers in a crystalline silicon substrate. This behaviour of the system can be explained by better passivation of surface States on the silicon substrate. The decrease in the efficiency of the solar cell after reaching the maximum is due to the increase of the resistance structure, which with a point contributes more to the characteristics of the solar cell than the contribution from the passivation of surface states. Using the PECVD method, amorphous silicon films with a thickness of 7, 30 and 50 nm were grown on a single-crystal commercial silicon substrate on both sides. Then, the lifetime of non-basic charge carriers was measured using the contactless Sinton method on these structures. Further, the samples were examined by photoluminescence at room temperature. Using this method, it was possible to obtain the dependence of the concentration of non-equilibrium charge carriers on the intensity of photoluminescence radiation. These dependences showed that the intensity is lower on samples with a lower thickness of amorphous silicon than in samples with a higher thickness of the amorphous layer. The detailed results of this work were first presented by the corresponding author in his dissertation [3], the theses of the work were presented at the conference of young scientists of KazNU [4] and only now the results are published as a full-fledged article in the journal.

Self-Aligned Epitaxial Cosi2 Formation From Multilayer Co/Ti-Si(100) by a Two-Step Rta Process

1993 ◽  
Vol 303 ◽  
Author(s):  
F. Hong ◽  
B.K. Patnaik ◽  
G.A. Rozgonyi ◽  
C.M. Osburn
Keyword(s):  
Surface Layer ◽  
Thermal Oxidation ◽  
Recent Work ◽  
Amorphous Layer ◽  
Deep Submicron ◽  
Annealing Process ◽  
Thermally Stable ◽  
Si Substrates ◽  
Nano Scale ◽  
Patterned Wafers

ABSTRACTWe have extended our recent work on nano-scale CoSi2 formation from Co/Ti(O)multilayers on Si(100) to a self-aligned epitaxial CoSi2 structure produced by a two-step RTA annealing process. Parallel oxide stripes/Si windows were produced on a 4-inch Si(100) wafer by thermal oxidation and patterning. Six layers of 20nm Co and 10nm Ti were deposited sequentially on the patterned wafers with Ti as the first layer. The wafers were then annealed at 550°C to 700°C in N2 using a lamp RTA system. XTEM and RBS showed that a 25nm CoSi layer formed at the interface after a 650°C, 60sec annealing. The unreacted layers above it and oxide were selectively removed leaving a residual amorphous layer and CoSi intact on the patterned Si substrates. A second annealing at 900'C for 10sec produced 20nm of epitaxial CoSi2 covered with an ∼10nm CoxTiy(O)Siz surface layer. The epitaxial CoSi2 layer was thermally stable up to 1000°C, had a resistivity of ∼20μΩ-cm, and consumed ∼300Å of Si, thereby satisfying the most stringent deep submicron device contact scaling requirements.

scholarly journals Tellurium - modified surface states of GaAs(001) and InAs(001)

1999 ◽  
Vol 29 (4) ◽  
pp. 823-827
Author(s):  
R. Claudino da Silva ◽  
A. C. Ferraz
Keyword(s):  
Surface States ◽  
Modified Surface

In-Situ HREM of A Surface Reconstruction of Si Surface With Molten Al at High Temperatures

1999 ◽  
Vol 5 (S2) ◽  
pp. 698-699
Author(s):  
S. Tsukimoto ◽  
S. Arai ◽  
H. Miyai ◽  
H. Saka
Keyword(s):  
High Vacuum ◽  
Chemical Properties ◽  
Amorphous Layer ◽  
Ultra High Vacuum ◽  
Surface Structures ◽  
Physical And Chemical Properties ◽  
Modified Surface ◽  
Physical And Chemical ◽  
And Chemical Properties

IntroductionThe morphology of Si surface has much effect on physical and chemical properties of the surface. It is well known that the structure of Si surface can be modified by deposition of metals, and extensive studies have been carried out on the modified surface structures of Si. These studies were carried out on clean surfaces of Si in an ultra-high vacuum (UHV). However recently, it has been shown by Kamino et al.[l] that molten Au atoms remove a surface amorphous layer on the Si surface, making the surface clean even in a non ultra-high vacuum. The present study is an extension to the previous one (Kamino et al.) and Si surfaces modified by-molten Al atoms in a conventional vacuum were observed by means of TEM.ExperimentalThe specimen used in this study was a mixture of pure Al particles and Si particles, the latter being prepared by crushing a Si single crystal into pieces.

scholarly journals Formation of Metal Oxides Based Surface Nanolenses and Their Optical Properties

2019 ◽  
Vol 2 (2) ◽  
pp. 73-74
Author(s):  
Laraib Syeda ◽  
Carmen Van Horn ◽  
Jiasheng Qian ◽  
Xuehua Zhang
Keyword(s):  
Optical Properties ◽  
Renewable Energy ◽  
Oleic Acid ◽  
Fossil Fuels ◽  
Annealing Process ◽  
Acid Water ◽  
Solvent Exchange ◽  
Light Refraction ◽  
Fluid Cell ◽  
The Ideal

An emerging resource in the production of renewable energy are nanolenses, due to their unique optical properties. Their ability to refract light makes it possible for them to focus light and convert it into other forms of energy; which reduces the need for burning fossil fuels.   nanolens, nanodroplets, optical properties, fluid cell, surface nanolens The formation of nanolenses occurs due to the process of solvent exchange. In this process, different concentrations of a ternary mixture comprising of oleic acid, water, and ethanol are used to create an ideal formation of nanodroplets. A mixture of iron (IV) chloride and manganese chloride is then washed over the droplets to create the droplet’s shell. The droplets are then annealed at 300°C in order to remove all excess liquid, leaving behind the hollow nanolenses. This process was carried out on two different substrates, silicon wafer and glass with similar results transpiring on both.  After various trials, it can be concluded that the ideal concentration ratio of oleic acid/water/ethanol is 4.25/30/70, as the lenses are homogeneous in size, volume, and distribution. Allowing them to remain intact through the annealing process. These findings can be applied to further studies in the use of nanolenses concerning light refraction, and the consequential production of renewable energy.

Epitaxial CeO2 Growth on Si (111) for SOI

1994 ◽  
Vol 341 ◽  
Author(s):  
L. Tye ◽  
T. Chikyow ◽  
N. A. El-Masry ◽  
S. M. Bedair
Keyword(s):  
Laser Ablation ◽  
Electrical Properties ◽  
Epitaxial Growth ◽  
Surface States ◽  
Amorphous Layer ◽  
Growth Conditions ◽  
Post Annealing ◽  
Interfacial States ◽  
Epitaxial Oxide ◽  
Lattice Matched

AbstractEpitaxial growth of CeO2 was obtained on the Si(111) surface by laser ablation in UHV atmosphere. However, a dual amorphous layer formed at the interface, yielding a CeO2/α:-CeOx/α-SiO2/Si(111) structure. This structure is speculated to be caused by a reaction occurring between Ce oxide and Si. Post annealing in O2 ambient caused the regrowth of CeO2, eliminated the α-CeOx layer, and increased the thickness of the SiO2 layer. The new CeO2/SiO2/Si(111) structure shows improved breakdown voltage and fewer interfacial states as observed by C-V and I-V measurements. The SiO2 is expected to tie surface states with Si, whereas the single crystal CeO2 will allow the epitaxial growth of lattice-matched Si on this insulating film. The effect of growth conditions and O2 annealing on both the structural and the electrical properties of this epitaxial oxide will be presented.

Sign in / Sign up

Export Citation Format

Share Document