Low-temperature VUV photoluminescence and thermoluminescence of UV excited afterglow phosphor Sr3AlxSi1−xO5:Ce3+,Ln3+ (Ln = Er, Nd, Sm, Dy and Tm)

2015 ◽  
Vol 17 (23) ◽  
pp. 15419-15427 ◽  
Author(s):  
Hongde Luo ◽  
Adrie J. J. Bos ◽  
Anna Dobrowolska ◽  
Pieter Dorenbos
Keyword(s):  
Low Temperature ◽  
Electron Traps ◽  
Recombination Centre

Low-temperature thermoluminescence measurements of Ce doped Sr3SiO5 show that Ce3+ is the recombination centre and Nd, Sm, Dy and Tm work as electron traps with trap depths of 0.95 eV, 1.89 eV, 1.02 eV, and 1.19 eV, respectively.

Dislocation-related deep states induced by irradiation in HVPE n-GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
A. Castaldini ◽  
A. Cavallini ◽  
L. Polenta
Keyword(s):  
Low Temperature ◽  
Point Defects ◽  
Pulse Width ◽  
Proton Irradiation ◽  
Diode Structure ◽  
Extended Defects ◽  
Electron Traps ◽  
Actual Existence ◽  
Site Density ◽  
Deep Traps

ABSTRACTThis paper deals with defects induced by proton irradiation in n-GaN. The samples were HVPE grown, irradiated with 24 GeV protons. DLTS was performed on both as-grown and irradiated samples with planar and normal collector configurations to evidence the dislocation effect. Two electron traps were identified in the as-grown material by both diode structures: trap EC1 (EC – 0.19eV) and trap EC2 (EC – 0.25eV), EC2 being the dominant one. Irradiation consistently affects the pre-existing levels in such a way so as their appearance strongly depends on the diode structure, hence on the region probed by DLTS.This contribution focuses on the actual existence of two deep traps EC1 and EC2 emitting in GaN at low temperature and on the different nature of the deep levels associated to EC1 and EC2. Their filling kinetics was studied since we supposed that EC2 would be associated to extended defects, as already reported in literature. Indeed, the site density of EC2 logarithmically depends on the filling pulse width, demonstrating that this trap is definitely associated to extended defects. The trap EC1, on the contrary, exhibits the filling kinetics peculiar of point defects.

Capacitance study of electron traps in low-temperature-grown GaAs

2004 ◽  
Vol 38 (4) ◽  
pp. 387-392 ◽  
Author(s):  
P. N. Brunkov ◽  
A. A. Gutkin ◽  
A. K. Moiseenko ◽  
Yu. G. Musikhin ◽  
V. V. Chaldyshev ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electron Traps ◽  
Low Temperature Grown Gaas

Capacitive Properties of MIS Structures with SiOx and SixOyNz Films Containing Si Nanoclusters

2016 ◽  
Vol 39 ◽  
pp. 162-168 ◽  
Author(s):  
A. Evtukh ◽  
Oleg Bratus’ ◽  
Volodymyr Ilchenko ◽  
Volodymyr Marin ◽  
Iegor Vasyliev
Keyword(s):  
Low Temperature ◽  
Differential Capacitance ◽  
Differential Capacity ◽  
Electron Traps ◽  
Low Temperature Annealing ◽  
Capacitive Properties ◽  
Temperature Dependences ◽  
Two Peaks ◽  
Mis Structures

he negative differential capacity has been observed in case of MIS structures with SiOx and SixOyNz films containing Si nanoclusters. It has been shown that existence of negative differential capacity depends on charge state of Si nanoclusters or electron traps　in the insulating matrix. In case of SixOyNz films the two peaks have been revealed in C-V characteristics connected with Si nanoclusters and electron traps. The low-temperature annealing of SixOyNz films in hydrogen passivates the electron traps caused by Si dangling bonds and as a result the peak in C-V characteristics connected with electron traps disappears. The following low-temperature annealing in vacuum caused the some effusion of hydrogen from the film and appearance of electron traps and connected with them capacity shoulder on C-V characteristics. It has been shown, that the frequency and temperature dependences of the negative differential capacitance in C-V curves can be successfully used for the determination of nanoclusters and traps parameters for the samples with the nanoclusters embedded in SiO2 or SixOyNz films.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Sign in / Sign up

Export Citation Format

Share Document