DETERMINE THE SIZE AND OXIDIZATION OF SILICON QUANTUM DOTS PREPARED BY THERMAL EVAPORATION METHOD

2003 ◽  
Vol 02 (04n05) ◽  
pp. 357-362
Author(s):  
T. Y. CHIEN ◽  
C. T. CHIA ◽  
T. C. LIN ◽  
S. C. LEE
Keyword(s):  
Quantum Dots ◽  
Raman Spectra ◽  
Thermal Evaporation ◽  
Life Time ◽  
Gas Pressure ◽  
Evaporation Chamber ◽  
Thermal Evaporation Method ◽  
Ar Gas ◽  
Average Size ◽  
Si Quantum Dots

Raman spectrum has been used to analyze the size of Silicon (Si) quantum dots (QDs) prepared by thermal evaporation. Si QDs were grown in thermal evaporation chamber with Ar gas presented. We determined the average size of the Si QDs by analyzing the optical phonon of Si QDs in Raman spectra. We found that the higher the Ar gas pressure in the chamber, the larger the average size of Si QDs grown by thermal evaporation. We found the Si dot size reaches a maximum, about 7.5 nm in diameter, when Ar gas pressure is about 2–3 torr. The oxidization of Si QDs is also observed by Raman spectra. The life time of oxidized process was about 46 days.

Photoluminescence of pure silicon quantum dots embedded in an amorphous silica wire array

2017 ◽  
Vol 5 (27) ◽  
pp. 6713-6717 ◽  
Author(s):  
Shunkai Lu ◽  
Bin Wu ◽  
Yuyang Sun ◽  
Yafei Cheng ◽  
Fan Liao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Amorphous Silica ◽  
Thermal Evaporation ◽  
Wire Array ◽  
Silicon Quantum Dots ◽  
Pure Silicon ◽  
Si Quantum Dots

Si quantum dots embedded in an amorphous silica wire array were first synthesized using thermal evaporation.

Fabrication and Structural and Optical Characterizations of GaN Nano and Micro Structures Grown by Thermal Evaporation Method

2012 ◽  
Vol 545 ◽  
pp. 88-92
Author(s):  
Leila Shekari ◽  
Abu Hassan Haslan ◽  
Hassan Zainuriah
Keyword(s):  
Thermal Evaporation ◽  
Lattice Mismatch ◽  
Thermal Evaporation Method ◽  
Evaporation Method ◽  
Ceramic Boat ◽  
Gas Atmosphere ◽  
Ar Gas ◽  
Micro Structures

Abstract. Gallium Nitride (GaN) nano and micro structures were grown on different substrates, such as ceramic boat and alumina plate using thermal evaporation method with commercial GaN powder under the flow of Argon (Ar) gas atmosphere. Micro structural studies by scanning electron microscopy (SEM) revealed the role of different substrates in the nucleation of the GaN nano and micro wires and ribbons. Additional structural and optical characterizations were performed using energy-dispersive X-ray spectroscopy (EDX) and photoluminescence (PL) spectroscopy. Results indicated that the nanowires and nanoribbons are of single-crystal hexagonal GaN and are more and less orderly in their growth with different substrates. The quality of growth of the GaN nanowires and nanoribbons for different substrates is highly dependent on the lattice mismatch between the nanowires and their substrates and it also depends on the conditions of the growth.

Large Scale Synthesis of Highly Pure Single Crystalline Tellurium Nanowires by Thermal Evaporation Method

2006 ◽  
Vol 6 (11) ◽  
pp. 3380-3383 ◽  
Author(s):  
Paritosh Mohanty ◽  
Jeunghee Park ◽  
Bongsoo Kim
Keyword(s):  
Large Scale ◽  
Thermal Evaporation ◽  
Inert Atmosphere ◽  
High Yield ◽  
Si Substrate ◽  
Thermal Evaporation Method ◽  
Single Crystalline ◽  
Vaporization Process ◽  
Ar Gas ◽  
Tellurium Nanowires

Single crystalline tellurium nanowires were successfully synthesized in large scale by a facile approach of vaporizing tellurium metal and condensing the vapor in an inert atmosphere onto a Si substrate. Tellurium was evaporated by heating at 300° C at 1 torr and condensed on the Si substrate at 100–150° C, in the downstream of argon (Ar) gas at a flow rate of 25 sccm for 30 min. The as-synthesized nanowires have diameters between 100–300 nm and lengths up to several micrometers. The single crystalline nanowires grew in a preferred [0001] direction. The obtained nanowires were highly pure as only tellurium metal was used in the vaporization process, and no other reagent, surfactant, or template were used for the growth. This low temperature and high-yield approach to the tellurium nanowires synthesis may facilitate its industrial production for various applications.

Gan Nanowire Growth by Thermal Evaporation Method

2012 ◽  
Vol 501 ◽  
pp. 276-280
Author(s):  
Leila Shekari ◽  
Abu Hassan Haslan ◽  
Hassan Zainuriah
Keyword(s):  
Gas Flow ◽  
Thermal Evaporation ◽  
Mixed Gas ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Transmission Electron ◽  
Gas Atmosphere ◽  
Ar Gas ◽  
Uniform Diameter ◽  
Different Diameters

In this research we introduce an inexpensive method to produce highly crystalline GaN Nanowires (NWs) grown on porous zinc oxide (PZnO) using commercial GaN powder, either in argon gas or combination of nitrogen and Ar gas atmosphere, by thermal evaporation. Morphological structural studies using transmission electron microscope (TEM) and scanning electron microscopy (SEM) measurements showed the role of porosity and different gas flowing, in the alignment and nucleation of these NWs. The NWs grown under flow of mix gases have very different diameters of between 50 and 200 nm, but those which were grown in Ar gas atmosphere, have rather uniform diameter of around 50 nm. The length of the GaN NWs was uniform, (around 10 µm). Optical and structural characterizations were performed by energy-dispersive X-ray spectroscopy (EDX) and high resolution X-ray diffraction (HR-XRD). Results revealed that these NWs are of single-crystal hexagonal GaN with [oooı] and [ıoīı] growth directions for the NWs grown under Ar and mixed gas flow.

X- ray diffraction and dielectric properties of PbSe thin films

2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan
Keyword(s):  
Thin Films ◽  
Thermal Activation ◽  
Thermal Evaporation ◽  
Thermal Activation Energy ◽  
Dielectric Constants ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.

Fabrication and Growth Mechanism of Zn1-xCdxO Nanotubes by Thermal Evaporation Method

2009 ◽  
Vol 24 (5) ◽  
pp. 998-1002
Author(s):  
Bo LIU ◽  
Fa-Zhan WANG ◽  
Gu-Zhong ZHANG ◽  
Chao ZHAO ◽  
Si-Cong YUAN
Keyword(s):  
Growth Mechanism ◽  
Thermal Evaporation ◽  
Thermal Evaporation Method ◽  
Evaporation Method
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