Site-Selective Photoluminescence Spectroscopy of Er-Implanted Wurtzite Gan Under Various Annealing Conditions

1998 ◽  
Vol 512 ◽  
Author(s):  
S. Kim ◽  
S. J. Rhee ◽  
X. Li ◽  
J. J. Coleman ◽  
S. G. Bishop
Keyword(s):  
Annealing Temperature ◽  
Broad Band ◽  
Optically Active ◽  
Thermally Activated ◽  
Annealing Temperatures ◽  
Annealing Conditions ◽  
Postimplantation Annealing ◽  
Recombination Centers ◽  
Pl Spectrum ◽  
Site Selective

ABSTRACTThe ˜1540 nm 4I13/2 → 4I15/2 emissions of Er3+ in Er-implanted GaN annealed at temperatures in the 400 to 1000 °C range were investigated to gain a better understanding of the formation and dissociation processes of the various Er3+ sites and the recovery of damage caused by the implantation with increasing annealing temperature (TA). The monotonic increase in the intensity of the broad defect photoluminescence (PL) bands with increasing TA proves that these are stable radiative recombination centers introduced by the implantation and annealing process. These centers cannot be attributed to implantation-induced damage that is removed by postimplantation annealing. Selective wavelength pumping of PL spectra at 6 K reveals the existence of at least nine different Er3+ sites in this Er-implanted semiconductor. Most of these Er3+ PL centers are attributed to complexes of Er atoms with defects and impurities which are thermally activated at different TA. Only one of the nine observed Er3+ PL centers can be pumped by direct 4f absorption and this indicates that it is the highest concentration Er3+ center and it represents most of the optically active Er3+ in the implanted sample. The fact that this Er3+ center cannot be strongly pumped by above-gap light or broad band below-gap absorption indicates that it is an isolated center, i.e. not complexed with defects or impurities. This 4f-pumped PL spectrum appears at annealing temperatures as low as 400°C, and although its intensity increases monotonically with increasing TA, the wavelengths and linewidths of its characteristic peaks are unaltered. The observation of this high quality Er3+ PL spectrum at low annealing temperatures illustrates that the crystalline structure of GaN is not rendered amorphous by the ion implantation. The increase of the PL intensities of the various Er3+ sites with increasing TA is due to the removal of competing nonradiative channels with annealing.

Tracing the Goss Orientation during Deformation and Annealing of an FeSi Single Crystal

2007 ◽  
Vol 550 ◽  
pp. 485-490 ◽  
Author(s):  
Dorothée Dorner ◽  
Yoshitaka Adachi ◽  
Kaneaki Tsuzaki ◽  
Stefan Zaefferer
Keyword(s):  
Single Crystal ◽  
Annealing Temperature ◽  
Thickness Reduction ◽  
Goss Texture ◽  
Annealing Temperatures ◽  
Annealing Conditions ◽  
Cold Rolled ◽  
Goss Orientation ◽  
Oriented Material ◽  
Oriented Single Crystal

A Goss-oriented single crystal was cold rolled up to 89 % thickness reduction, and subsequently annealed at 550°C or 850°C. During deformation most of the initially Goss-oriented material rotated into the two symmetrical {111}<112> orientations. In addition, Goss regions were observed related to microbands or microshear bands. Goss regions in microshear bands formed during straining, whereas Goss regions between microbands were retained from the initial Goss orientation. The recrystallisation texture for annealing temperatures of both 550°C and 850°C is characterised by a Goss texture. However, the origin of the Goss recrystallisation nuclei appeared to be different for the different annealing conditions. In the material annealed at 550°C, the Goss texture originated from the Goss regions in the microshear bands. In contrast, for an annealing temperature of 850°C, the Goss grains between the microbands are likely to form recrystallisation nuclei.

Mechanisms of Formation of Thin Buried Oxide Layers by Ion Implantation

1987 ◽  
Vol 93 ◽  
Author(s):  
Alice E. White ◽  
K. T. Short ◽  
L. N. Pfeiffer ◽  
K. W. West
Keyword(s):  
Substrate Temperature ◽  
Annealing Temperature ◽  
Oxide Formation ◽  
Thermally Activated ◽  
Buried Oxide ◽  
Annealing Conditions ◽  
Mechanisms Of Formation ◽  
Substrate Temperatures ◽  
Thermally Activated Process

ABSTRACTWe have studied buried oxide formation as a function of implantation and annealing conditions. The layers appear to form via a nucleation and growth process, so the quality of the oxide and the perfection of the overlying crystalline Si layer depend more strongly on the substrate temperature during implantation than on the annealing temperature. Since it is easier to observe the layer formation process in a thin (<1000Å) layer, we concentrated on sub-stoichiometric doses and chose substrate temperatures below 400°C to stay in a homogeneous nucleation regime. Then we varied the annealing temperature from 1150°C to 1407°C. Modeling the coalescence of the oxide layer as a thermally-activated process yields activation energies of approximately 6 eV, suggesting that crystalline damage removal may be the bottleneck for this substrate temperature regime.

scholarly journals Structural and Optical Characterization of ZnS Ultrathin Films Prepared by Low-Temperature ALD from Diethylzinc and 1.5-Pentanedithiol after Various Annealing Treatments

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3212 ◽  
Author(s):  
Maksymilian Włodarski ◽  
Urszula Chodorow ◽  
Stanisław Jóźwiak ◽  
Matti Putkonen ◽  
Tomasz Durejko ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ultrathin Films ◽  
Quantum Confinement ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Sphalerite Structure ◽  
Annealing Temperatures ◽  
Annealing Conditions ◽  
Layer Deposition

The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures ≥400 °C and annealing time ≥2 h, and 1:1 stoichiometry was obtained when annealed at 500 °C for 4 h. ZnS crystallized into small crystallites (1–7 nm) with cubic sphalerite structure, which remained stable under the applied annealing conditions. The size of the crystallites (D) tended to decrease with annealing temperature, in agreement with the EDS data (decreased content of both S and Zn with annealing temperature); the D for samples annealed at 600 °C (for the time ≤2 h) was always the smallest. Both reflectivity and ellipsometric spectra showed characteristics typical for quantum confinement (distinct dips/peaks in UV spectral region). It can thus be concluded that the amorphous ZnS layer obtained at a relatively low temperature (150 °C) from organic S precursor transformed into the layers built of small ZnS nanocrystals of cubic structure after annealing at a temperature range of 300–600 °C under Ar atmosphere.

Improvement of the Specific Contact Resistance on P-Type 4H-SiC by Using a Highly P-Typed Doped 4H-SiC Layer Selectively Grown by VLS Transport

2014 ◽  
Vol 806 ◽  
pp. 57-60
Author(s):  
Nicolas Thierry-Jebali ◽  
Arthur Vo-Ha ◽  
Davy Carole ◽  
Mihai Lazar ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Schottky Barrier Height ◽  
Annealing Temperature ◽  
Process Condition ◽  
Specific Contact Resistance ◽  
High Doping Level ◽  
Annealing Temperatures ◽  
Specific Contact ◽  
P Type

This work reports on the improvement of ohmic contacts made on heavily p-type doped 4H-SiC epitaxial layer selectively grown by Vapor-Liquid-Solid (VLS) transport. Even before any annealing process, the contact is ohmic. This behavior can be explained by the high doping level of the VLS layer (Al concentration > 1020 cm-3) as characterized by SIMS profiling. Upon variation of annealing temperatures, a minimum value of the Specific Contact Resistance (SCR) down to 1.3x10-6 Ω.cm2 has been obtained for both 500 °C and 800 °C annealing temperature. However, a large variation of the SCR was observed for a same process condition. This variation is mainly attributed to a variation of the Schottky Barrier Height.

Structural Changes of UHV Deposited Titanium Thin Films in Presence of Oxygen Flow and Temperature

2011 ◽  
Vol 110-116 ◽  
pp. 1094-1098
Author(s):  
Haleh Kangarlou ◽  
Mehdi Bahrami Gharahasanloo ◽  
Akbar Abdi Saray ◽  
Reza Mohammadi Gharabagh
Keyword(s):  
Room Temperature ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Annealing Process ◽  
Oxygen Flow ◽  
Glass Substrates ◽  
Annealing Temperatures ◽  
Titanium Thin Films ◽  
Deposition Angle ◽  
Ti Films

Ti films of same thickness, and near normal deposition angle, and same deposition rate were deposited on glass substrates, at room temperature, under UHV conditions. Different annealing temperatures as 393K, 493K and 593K with uniform 8 cm3/sec, oxygen flow, were used for producing titanium oxide layers. Their nanostructures were determined by AFM and XRD methods. Roughness of the films changed due to annealing process. The gettering property of Ti and annealing temperature can play an important role in the nanostructure of the films.

scholarly journals Experimental Investigation on Micro Deep Drawing of Stainless Steel Foils with Different Microstructural Characteristics

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jingwei Zhao ◽  
Tao Wang ◽  
Fanghui Jia ◽  
Zhou Li ◽  
Cunlong Zhou ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Deep Drawing ◽  
Annealing Temperature ◽  
Localized Deformation ◽  
Microstructural Characteristics ◽  
Height Profile ◽  
Annealing Temperatures ◽  
Micro Deep Drawing ◽  
Profile Distribution

AbstractIn the present work, austenitic stainless steel (ASS) 304 foils with a thickness of 50 µm were first annealed at temperatures ranging from 700 to 1100 ℃ for 1 h to obtain different microstructural characteristics. Then the effects of microstructural characteristics on the formability of ASS 304 foils and the quality of drawn cups using micro deep drawing (MDD) were studied, and the mechanism involved was discussed. The results show that the as-received ASS 304 foil has a poor formability and cannot be used to form a cup using MDD. Serious wrinkling problem occurs on the drawn cup, and the height profile distribution on the mouth and the symmetry of the drawn cup is quite non-uniform when the annealing temperature is 700 ℃. At annealing temperatures of 900 and 950 ℃, the drawn cups are both characterized with very few wrinkles, and the distribution of height profile, symmetry and mouth thickness are uniform on the mouths of the drawn cups. The wrinkling becomes increasingly significant with a further increase of annealing temperature from 950 to 1100 ℃. The optimal annealing temperatures obtained in this study are 900 and 950 ℃ for reducing the generation of wrinkling, and therefore improving the quality of drawn cups. With non-optimized microstructure, the distribution of the compressive stress in the circumferential direction of the drawn foils becomes inhomogeneous, which is thought to be the cause of the occurrence of localized deformation till wrinkling during MDD.

Effect of Intercritical Annealing Temperature on Development of Cold Rolled Dual Phase Steel from Q345 Steel

2013 ◽  
Vol 313-314 ◽  
pp. 693-696
Author(s):  
Ji Yuan Liu ◽  
Fu Xian Zhu ◽  
Shi Cheng Ma
Keyword(s):  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Simulation Experiment ◽  
Intercritical Annealing ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Automotive Applications ◽  
Treatment Procedure ◽  
Annealing Temperatures ◽  
Cold Rolled

Cold rolled dual phase steel was developed from Q345 steel by heat treatment procedure for automotive applications. The ultimate tensile strength was improved about 100MPa higher than the traditional cold-rolled Q345 steel in the continuous annealing simulation experiment. The microstructure presented varied characteristics in different intercritical annealing temperatures; mechanical properties were changed correspondingly as well. The chief discussions are focus on the recrystallization, hardenability of austenite and martensite transformation in the experiment.

SPM Characterization of Substrate Surfaces Prepared for Carbon-Related-Film Deposition

1999 ◽  
Vol 587 ◽  
Author(s):  
Kazumasa Narumi ◽  
Shunya Yamamoto ◽  
Hiroshi Naramoto
Keyword(s):  
Annealing Temperature ◽  
Temperature Characteristic ◽  
Film Deposition ◽  
Annealing Conditions ◽  
Atomic Force ◽  
Surface Steps ◽  
Order Of Magnitude ◽  
Reducing Environment ◽  
Substrate Surfaces

AbstractsVariation of surface steps on sapphire (0001) and (1120) substrates processed with thermal annealing in air or a reducing environment at 1000 to 1400°C for 1 to 10 hours were investigated with an atomic force microscope (AFM). The annealed (0001) surfaces consist of atomically smooth and large terraces and atomic-height steps, whose configurations strongly depend on annealing conditions. On the (1120) surfaces, where crystallographic misorientation is almost an order of magnitude larger than that of the (0001) surfaces, step height and terraces increase in size with the longer annealing time and higher annealing temperature. Characteristic step figures due to the symmetry of atomic arrangement were observed on the (0001) surface.

Optical Waveguide Formation by Ion Implantation of Ti or Ag

1988 ◽  
Vol 100 ◽  
Author(s):  
D. B. Poker ◽  
D. K. Thomas
Keyword(s):  
Ion Implantation ◽  
Concentration Profile ◽  
Optical Waveguides ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Effective Means ◽  
Complete Removal ◽  
Solid Phase Epitaxy ◽  
Annealing Temperatures ◽  
Residual Damage

ABSTRACTIon implantation of Ti into LINbO3 has been shown to be an effective means of producing optical waveguides, while maintaining better control over the resulting concentration profile of the dopant than can be achieved by in-diffusion. While undoped, amorphous LiNbO3 can be regrown by solid-phase epitaxy at 400°C with a regrowth velocity of 250 Å/min, the higher concentrations of Ti required to form a waveguide (∼10%) slow the regrowth considerably, so that temperatures approaching 800°C are used. Complete removal of residual damage requires annealing temperatures of 1000°C, not significantly lower than those used with in-diffusion. Solid phase epitaxy of Agimplanted LiNbO3, however, occurs at much lower temperatures. The regrowth is completed at 400°C, and annealing of all residual damage occurs at or below 800°C. Furthermore, the regrowth rate is independent of Ag concentration up to the highest dose implanted to date, 1 × 1017 Ag/cm2. The usefulness of Ag implantation for the formation of optical waveguides is limited, however, by the higher mobility of Ag at the annealing temperature, compared to Ti.

Effects of Annealing Temperature on Morphology and Dielectric Property of BiFeO3 Films

2012 ◽  
Vol 512-515 ◽  
pp. 1736-1739
Author(s):  
Li Li Zhang ◽  
Guo Qiang Tan ◽  
Meng Cheng ◽  
Hui Jun Ren ◽  
Ao Xia
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Property ◽  
Annealing Temperature ◽  
Raw Materials ◽  
Sol Gel ◽  
Frequency Range ◽  
Annealing Temperatures ◽  
Pure Phase ◽  
Lower Loss

Fe(NO3)3•9H2O and Bi(NO3)3•5H2O were used as raw materials. BiFeO3 thin films were prepared by sol-gel method. The effects of annealing temperatures on the morphology and dielectric property of the thin films were studied. XRD results show that the multi-crystal thin films with pure phase are obtained when annealed at 500°C and 550°C. But annealing at 580°C will lead to the appearance of Bi2.46Fe5O12 phase.AFM images show that as the increase of annealing temperatures the surface toughness of the thin film is decreased, but the surface undulation of the thin films is decreased gradually. Within the frequency range of 1KHz~1MHz, the dielectric constant of BiFeO3 thin films is kept over 125 and it does not change very much from 500°C to 580°C. Annealed at 550°C, the BiFeO3 thin films with the lower loss are obtained. At 1MHz, the dielectric loss is 0.12.

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