Phosphorus Passivation of GaAs

1998 ◽  
Vol 510 ◽  
Author(s):  
S.P. Watkins ◽  
X. Xu ◽  
J. Hu ◽  
R. Ares ◽  
P. Yeo ◽  
...  
Keyword(s):  
Room Temperature ◽  
Thin Layers ◽  
Difference Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Reflectance Difference Spectroscopy ◽  
Similar Chemical ◽  
Pl Intensity ◽  
Undoped Gaas

AbstractWe have performed a systematic study of the effect of various phosphorus passivation techniques on the room temperature photoluminescence (PL) intensity of undoped GaAs. The effects of passivation by two methods are compared: (1) the P-exchange reaction on exposure to tertiarybutylphosphine (TBP) vapour between 500-620°C, and (2) the growth of thin layers of GaP directly on GaAs. An x-ray diffraction technique was used to estimate the thickness of the passivating layers. Reflectance difference spectroscopy indicated a similar chemical origin for the two passivation methods. Both passivation techniques resulted in strong enhancements in the room temperature PL. PL intensity was observed to increase very rapidly with adsorbed P for both cases saturating at approximately 2 monolayers equivalent GaP coverage.

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

Growth mechanism and characterization of ZnO nano-tubes synthesized using the hydrothermal-etching method

2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Yan Li ◽  
Chuan-Sheng Liu ◽  
Yun-Ling Zou
Keyword(s):  
Room Temperature ◽  
Morphological Analysis ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Etching Method ◽  
Nano Rods ◽  
Two Stages

AbstractZnO nano-tubes (ZNTs) have been successfully synthesized via a simple hydrothermal-etching method, and characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The as-synthesized ZNTs have a diameter of 500 nm, wall thickness of 20–30 nm, and length of 5 µm. Intensity of the plane (0002) diffraction peak, compared with that of plane (10$$ \bar 1 $$0) of ZNTs, is obviously lower than that of ZnO nano-rods. This phenomenon can be caused by the smaller cross section of plane (0002) of the nano-tubes compared with that of other morphologies. On basis of the morphological analysis, the formation process of nano-tubes can be proposed in two stages: hydrothermal growth and reaction etching process.

Determination of growth parameters for atomic layer epitaxy using reflectance difference spectroscopy

1996 ◽  
Vol 74 (S1) ◽  
pp. 85-88 ◽  
Author(s):  
R. Arès ◽  
C. A. Tran ◽  
S. P. Watkins
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Gas Flows ◽  
Difference Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reflectance Difference Spectroscopy

Reflectance difference spectroscopy (RDS) has been used to monitor the anisotropy of the surface of InAs and GaAs grown by atomic layer epitaxy (ALE). Saturation of the RDS signal is observed when the surface is fully covered with one monolayer of the impinging surface species. This property is used to optimize the growth interruptions for the ALE cycle. Good correlation of the RDS saturation is observed with growth-rate measurements obtained by X-ray diffraction (XRD). When exposure times are sufficiently long for saturation to be observed in the RDS signal, a growth rate of one monolayer per cycle (1 ML/cycle) is achieved. In principle all the different growth parameters such as exposure and purge times as well as gas flows can be determined in a few cycles performed on a single substrate. Without RDS the same results would require several growth runs and time consuming X-ray characterization.

PREPARATION OF LUMINESCENT PbWO4 MICROCRYSTALS WITH HIERARCHICAL STRUCTURES BY USING MICROWAVE IRRADIATION HEATING METHOD

2010 ◽  
Vol 24 (32) ◽  
pp. 3081-3087 ◽  
Author(s):  
GENGPING WAN ◽  
GUIZHEN WANG
Keyword(s):  
Electron Microscopy ◽  
Microwave Irradiation ◽  
Room Temperature ◽  
Hierarchical Structures ◽  
X Ray Diffraction ◽  
Lead Tungstate ◽  
Heating Method ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Scanning Electron

Lead tungstate ( PbWO 4) microcrystals with hierarchical structures have been successfully synthesized via a facile microwave irradiation heating method. The cetyltrimethylammonium bromine (CTAB) and microwave-heated power were found to play an important role in the morphological control of resulting PbWO 4 mirocrystals. The products were characterized by the techniques of powder X-ray diffraction and field-emission scanning electron microscopy. A growth mechanism of PbWO 4 microstructures was proposed. The luminescence properties of the final products were investigated and the as-prepared PbWO 4 microcrystals displayed a very unique room-temperature photoluminescence compared to the reported results.

EFFECT OF VANADIUM CONTENT ON PHOTOLUMINESCENCE AND MAGNETIC PROPERTIES OF DOPED ZnO THIN FILMS

2010 ◽  
Vol 24 (10) ◽  
pp. 945-951 ◽  
Author(s):  
LIWEI WANG ◽  
ZHENG XU ◽  
SULING ZHAO ◽  
LIFANG LU ◽  
FUJUN ZHANG
Keyword(s):  
Photoluminescence Spectrum ◽  
Room Temperature ◽  
Doping Concentration ◽  
Vanadium Content ◽  
X Ray Diffraction ◽  
Vanadium Concentration ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Room Temperature Photoluminescence Spectrum ◽  
Diffraction Patterns

ZnO : V thin films with different doping concentration (0%, 1.8%, 3.9%, 6.8%, 10%, and 13%) were fabricated by direct current magnetron sputtering. The X-ray diffraction patterns show that the wurzite structure changed with doping concentration. Furthermore, we could not find any vanadium cluster or phase separation in the X-ray diffraction patterns. The photoluminescence of ZnO : V with different vanadium concentration was investigated. The room temperature photoluminescence spectrum indicates that the films have purple band with 370 nm and the bands with 475 and 490 nm. The peak intensity of room temperature photoluminescence spectrum was affected by vanadium contents and its position remained stable. The intensity of band with 370 nm increases with raising the vanadium concentration and then decreases. The hysteresis behavior indicates that films were ferromagnetic at 50 K. Room temperature ferromagnetism was observed for the film with the doping concentration at 6.8%. However, in this case almost no hysteresis is noticeable. The results implied that the doping concentration and crystalline microstructure influence strongly the film's magnetic characteristics. Increasing the vanadium content in the film caused the degradation of the magnetic ordering.

Mn, Cu Doping and Optical Properties of Highly Crystalline Ultralong ZnS Nanowires

2007 ◽  
Vol 31 ◽  
pp. 114-116 ◽  
Author(s):  
N.D. Chien ◽  
H.V. Chung ◽  
P.T. Huy ◽  
Do Jin Kim ◽  
Maurizio Ferrari
Keyword(s):  
Room Temperature ◽  
Doping Concentration ◽  
Thermal Evaporation ◽  
X Ray Diffraction ◽  
Cu Doping ◽  
Mn Doping ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Single Crystal Structures ◽  
Scanning Electron

Manganese (Mn) and copper (Cu) doping of ZnS nanowires was achieved by thermal evaporation of Mn, Cu doped ZnS nanopowders. Field emission scanning electron microscopy, and X-ray diffraction studies of the obtained ZnS nanowires demonstrate that the nanowires are single crystal structures and have diameters about 30-200 nm and lengths up to 1 millimeter. Room temperature photoluminescence (PL) measurements show a common PL peak around 520 nm for all ZnS nanowires samples, while impurity-related emission band are observed in doped ZnS nanowires. The dependence of the PL intensity on Mn doping concentration has also been investigated. It is shown that for high Mn doping concentration (10%) in the starting ZnS nanopowders, new emission bands (orange-red and red bands) are observed from the ZnS:Mn nanowires products. The origins of these new emission bands are discussed and brought up for further discussion.

Photoluminescence and Structural Characteristics of SnO2 Nanopetals Synthesized by Thermal Evaporation

2010 ◽  
Vol 152-153 ◽  
pp. 697-701
Author(s):  
Bing Wang ◽  
Ling Li
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
Structural Characteristics ◽  
The Self ◽  
Silicon Substrates ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Sno2 Nanostructure

A new nanostructure, (2D) nanopetal of SnO2, has been grown on single silicon substrates by Au-Ag alloying catalyst assisted carbothermal evaporation of SnO2. Field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and Raman are employed to identify the morphology and structure of the synthesized productions. Room-temperature photoluminescence (PL) is used to characterize the luminescence of SnO2 nanostructure. Three new peaks at 356, 450 and 489 nm in the measured photoluminescence spectra are observed, implying that more luminescence centers exist in SnO2 nanopetals due to nanocrystals and defects. The growth of the SnO2 nanopetals is discussed on the basis of the self-catalyst mechanism.

Combined Room Temperature Photoluminescence And High Resolution X-Ray Diffraction Mapping Of Semiconductor Wafers

1995 ◽  
Vol 406 ◽  
Author(s):  
S Cockerton ◽  
M L Cooke ◽  
D K Bowen ◽  
B K Tanner
Keyword(s):  
High Resolution ◽  
Room Temperature ◽  
Poisson Ratio ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition Variation ◽  
Line Context ◽  
And Performance

AbstractWe describe the characteristics and performance of a combined desk-side high resolution X-ray diffractometer and room temperature photoluminescence spectrometer designed for rapid mapping of compound semiconductors in a production line context. The combined data for AIGaAs on GaAs suggest that recent measurements of the lattice constant and the Poisson ratio of AlAs may be more reliable than earlier published values. We illustrate the instrument performance in showing that for lattice matched ternary GaInP on GaAs systems, the X-ray rocking curve maps are much more sensitive to composition variation than the photoluminescence spectra.

Synthesis and Photoluminescence Properties of Sm3+-Doped Ca10(PO4)6(OH)2 Nanowire

2011 ◽  
Vol 391-392 ◽  
pp. 1123-1127
Author(s):  
Qi Xiao ◽  
Lan Gao
Keyword(s):  
Electron Microscope ◽  
Emission Intensity ◽  
Room Temperature ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Transmission Electron ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis

The Sm3+-doped Ca10(PO4)6(OH)2 nanowires are synthesized by hydrothermal method. X-ray diffraction confirmed that the nanowires are made of the hexagonal Ca10(PO4)6(OH)2. Scanning electron microscope and transmission electron microscope analysis show that the lengths of the nanowires are approximately 5μm, and their diameters are around 100 nm, and the aspect (length/diameter) ratio is about 50. The room temperature photoluminescence (PL) spectra of Sm3+-doped Ca10(PO4)6(OH)2 nanowires doped with different Sm3+ concentration under 405 nm excitation has been investigated. It is found that there are three main sharp emissions peaks at near 569, 604, and 649 nm. The three emissions are due to the f-f forbidden transitions of the 4f electrons of Sm3+, corresponding to 4G5/2→6H5/2 (569 nm), 6H7/2(604 nm), and 6H9/2(649 nm), respectively. In addition, concentration quenching is also observed. It is found that the Sm3+4G5/2→6H7/2(604 nm) emission intensity of Sm3+-doped Ca10(PO4)6(OH)2 nanowires significantly increases with the increase of Sm3+ concentration, and shows a maximum when Sm3+ doping content is 0.5%. If Sm3+ concentration continues to increase, namely more than 0.5%, the Sm3+4G5/2→6H7/2 emission intensity decreases.

Research on Photoluminescence Characteristics of the Active Cl-Doped ZnS

2011 ◽  
Vol 284-286 ◽  
pp. 2276-2279 ◽  
Author(s):  
Hua Zhang ◽  
Jun Cheng Liu ◽  
Jiao Li
Keyword(s):  
Room Temperature ◽  
Wave Length ◽  
X Ray Diffraction ◽  
Excitation Wave ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Maximum Peak ◽  
Green Photoluminescence ◽  
Structural Characterizations ◽  
Blue Photoluminescence

A active Cl-doping for photoluminescent ZnS powder has been carried out by thermal decomposed AlCl3·6H2O in a quartz tube. Room temperature photoluminescence of the Cl-doped ZnS powder has been investigated using a photoluminescence spectrometer with 365 nm excitation wave length. A strong blue photoluminescence with maximum peak about 450 nm and green photoluminescence with maximum peak about 500 nm can be observed if the doping temperature in range of 800 ~ 900 °C and 1100 ~1200 °C, respectively. The structural characterizations of the Cl-doped ZnS powders were performed with X-ray diffraction (XRD) and the mechanism of photoluminescence was preliminarily discussed.

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