More documents

Recommendations

Info

I [A] 10 -3 10 -4 10 -5 320K 10 -6 10 -7 10 -8 10 -9 180K 10 -10 10 -11 Βήμα 20Κ 10 -12 10 -13 10 -14 Φ=1.57x10 12 cm -2 0.0 0.5 1.0 1.5 2.0 V [V] Σχήμα 1: Χαρακτηριστικές ρεύματος-τάσης (I-V) σε περιοχή θερμοκρασιών 180-320Κ με βήμα 20Κ και σε δόση ακτινοβολίας 1.57x10 12 cm -2 . I [mA] 0.5 0.4 0.3 0.2 0.1 0.0 πριν την ακτινοβόληση Φ=1.57x10 12 cm -2 Τ=300Κ 0.0 0.5 1.0 1.5 2.0 V [ V ] Σχήμα 2: Χαρακτηριστικές καμπύλες ρεύματος-τάσης (I- V) πριν την ακτινοβόληση και για δόση ακτινοβολίας 1.57x10 12 cm -2 . C [pF] 250 200 150 100 50 Φ=1.57x10 12 cm -2 310K 270K 240K 210K 180K 0 -10 -8 -6 -4 -2 0 2 V [V] C [pF] 300 250 200 150 T=200K Φ 2 Φ 1 = 9.8x10 10 cm -2 Φ 2 =7.8x10 11 cm -2 Φ 3 =1.57x10 12 cm -2 Φ 3 100 50 -10 -8 -6 -4 -2 0 2 V [V] Φ 1 Σχήμα 3: Διάγραμμα της χωρητικότητας σε συνάρτηση με την τάση πόλωσης για περιοχή θερμοκρασιών 180-310Κ με βήμα 30Κ και για δόση ακτινοβολίας 1.57x10 12 cm -2 . Σχήμα 4: Διάγραμμα της χωρητικότητας σε συνάρτηση με την τάση πόλωσης σε θερμοκρασία Τ=200Κ για δόσεις ακτινοβολίας 9.8x10 10 cm -2 , 7.8x10 11 cm -2 και 1.57x10 12 cm -2 42
Annealing Induced Dissociation of N 2 Formed in Indium Implanted GaN M. Katsikini 1* , E. C. Paloura 1 , F. Boscherini 2 , E. Wendler 3 , W. Wesch 3 . 1 Aristotle University of Thessaloniki, School of Physics, Section of Solid State Physics, 54124 Thessaloniki, Greece 2 Department of Physics and CNISM, University of Bologna, viale C. Berti Pichat 6/2, 40127 Bologna, Italy 3 Institut fur Festkörperphysik, Friedrich-Schiller Universität Jena, Max-Wien-Platz 1, 07743, Germany *katsiki@auth.gr InGaN/GaN heterostructures find applications in the fabrication of high efficiency light emitting diodes as well as in high – frequency, high – power microelectronic devices [1]. Ion implantation followed by annealing is a promising method for the growth of nanomaterials [2,3], like InGaN quantum dots, which enhance the emission characteristics of InGaN – based laser diodes [4], and InGaN/GaN heterostructures. For example, high dose Ge implantation in Si has been proposed as a method for the fabrication of Si x Ge y /Si heterostructures [5]. Although ion implantation has the advantage of precise dose and profile control, it causes lattice damage which can be recovered via annealing. Here, we apply near edge x-ray absorption fine structure (NEXAFS) spectroscopy at the N K edge, in order to determine the implantation induced changes in the electronic structure of GaN samples. XAFS spectroscopies are ideally suited for the study of highly defective or amorphous materials, such as implanted samples, since the main mechanism involved is the backscattering of the outgoing photoelectron wave from the neighboring atoms which does not depend on the periodicity of the lattice. More specifically, we focus on the identification and thermal stability of N 2 gaseous bubbles that have been proposed [6] as an implantation induced defect in ion implanted GaN. The 450nm – thick – GaN sample was grown on Al 2 O 3 by Plasma Enhanced Molecular Beam Epitaxy using an AlN buffer layer [7]. The sample was diced and the individual pieces were implanted at 77 K with 700 keV In ions with a fluence of 5 × 10 15 cm -2 . Rutherford backscattering characterization has 4 shown that a 200 µm thick amorphous layer is formed on the surface of the sample, while the remaining GaN sample is severely defected. as grown The implanted samples were subjected to rapid thermal annealing (RTA) at 800 o and 900 o C for 15 sec. The N K edge NEXAFS 3 ann. (900 o C) measurements were conducted at the ALOISA undulator beamline of the Synchrotron Radiation facility ELETTRA in Trieste. The spectra were recorded in the fluorescence yield ann. (800 o C) mode using a high purity Ge detector cooled at RL 77K. In order to avoid polarisation effects, the 2 angle of incidence was equal to the magic as implanted angle (55 o to the sample surface). The information depth of the fluorescence photons is approximately equal to 40nm. The N K edge NEXAFS spectra of the as – implanted and the annealed samples are shown in Fig. 1. In the same Figure the spectrum of N 2 , which fills an ionization chamber (2×10 -8 mbar) positioned in front of the sample, is also included. As shown in the Figure, implantation smears out the NEXAFS peaks that characterize the spectrum of the asgrown sample while at the same time causes the evolution of a sharp resonance line (RL), which appears above the absorption edge. The energy center of the RL coincides with the one which corresponds to 1s π * transitions of N 2 , as it is evident in Fig. 1. Thus, the implantation induced RL can be attributed to the implantation induced formation of N 2 . Similar RLs have been reported in the Intensity (arb. units) 1 0 390 400 410 420 430 440 Energy (eV) literature in a number of occasions. Katsikini et al reported the evolution of a sharp RL above the absorption edge in the fluorescence spectra of GaN implanted with O, N, Mg and Si [8]. The RL was attributed to transitions to final states related to N dangling bonds due to the independency of its energy position and full width at half maximum from the nature of the projectile and its similarity with the RL observed in the electron energy loss spectra recorded from the core of threading dislocations [9]. Furthermore, a similar RL, attributed to 1s π* transitions of N 2 trapped in the semiconductor, has been detected in the surface sensitive electron yield spectra of bulk semiconductors bombarded with low energy N 2 + [10] and in N N 2 Figure 1: N K edge NEXAFS spectra of the as-grown, as-implanted and annealed GaN:In samples. The spectrum of molecular nitrogen is also included in the figure. 43
Page 1 and 2:
XXIII ΠΑΝΕΛΛΗΝΙΟ ΣΥΝΕ
Page 3 and 4:
Κοιτώντας τα πρακτ
Page 5 and 6:
ΕΠΙΤΡΟΠΕΣ Οργανωτι
Page 7 and 8:
ΠΡΟΓΡΑΜΜΑ ΣΥΝΕΔΡΙΟ
Page 9 and 10: 21. Οργανικά τρανζίσ
Page 11 and 12: 15:30 15:45 16:00 16:15 16:30 16:45
Page 13 and 14: 41. Modeling and quantitative phase
Page 15 and 16: Ανοιχτή Συνεδρία «
Page 17 and 18: «NανοΥλικά και Νανο
Page 19 and 20: New materials and MOS device concep
Page 21 and 22: Reliability Characteristics of Rare
Page 23 and 24: Ο λόγος των ταχυτήτ
Page 25 and 26: Thus the mean R In-In is expected t
Page 27 and 28: FIG 1. Schematic representation of
Page 29 and 30: με 0.80 eV στη διεπιφά
Page 31 and 32: Εντοπισµός Φορέων
Page 33 and 34: Παρασκευή και Xαρακ
Page 35 and 36: Electrical Spin Injection from Fe i
Page 37 and 38: Electrical Spin Injection of Spin-P
Page 39 and 40: References [1] CH Lee, J. Meteer, V
Page 41 and 42: Σχήμα 1: Φωτογραφία
Page 43 and 44: SEM Image Layout Simulation Εικ
Page 45 and 46: Μελέτη Ατελειών Σε
Page 47 and 48: Facet-Stress-Driven Ordering in SiG
Page 49 and 50: νανοκρυσταλλίτης (a
Page 51 and 52: Σχήµα 1. Εικόνες περ
Page 53 and 54: Σχήµα 1. Εικόνες περ
Page 55 and 56: Οι δομές που αναπτύ
Page 57 and 58: Raman Intensity (10 -50 cm 3 ) 1,2
Page 59: Μελέτη της Επίδρασ
Page 63 and 64: `Εναπόθεση με Παλμι
Page 65 and 66: Μελέτη της Χημείας
Page 67 and 68: Ανάπτυξη Νέων Μεσο
Page 69 and 70: Application of Thermal Quadrupoles
Page 71 and 72: Στοχαστική προσομο
Page 73 and 74: Νανοτραχύτητα κατά
Page 75 and 76: Ευαισθησία και Δια
Page 77 and 78: Optical Properties of CuIn 1-x Ga x
Page 79 and 80: ανοπτημένο με λέιζ
Page 81 and 82: Στο σχήμα 3 φαίνοντ
Page 83 and 84: Id (mA) -0,3 -0,2 -0,1 Vg=0 Vg=-1 V
Page 85 and 86: Strained-Si Si 1-x Ge x graded Si 1
Page 87 and 88: Fig. 1. Laser mask movement during
Page 89 and 90: forwarded to the back interface dur
Page 91 and 92: Σχήμα 2: Εκθετική εξ
Page 93 and 94: V th (V) G m,max /G m,max0 (%) I d
Page 95 and 96: C/ C ox 1,0 0,8 0,6 0,4 0,2 0,0 -4
Page 97 and 98: και Ta 2 O 5 , των οποίω
Page 99 and 100: κατασκευή της. Η πα
Page 101 and 102: ΔP (mW) 12 10 8 6 4 2 0 0 500 1000
Page 103 and 104: υπολογίσουμε θεωρη
Page 105 and 106: Σχήμα 2 Σύστημα ηλε
Page 107 and 108: Μελέτη των Μηχανισ
Page 109 and 110: Ανάπτυξη και Μελέτ
Page 111 and 112:
Structure and Magnetic Properties o
Page 113 and 114:
Δομή και Μαγνητικέ
Page 115 and 116:
Μετρήσεις Ειδικής
Page 117 and 118:
Further, almost all of the observed
Page 119 and 120:
g-factor 2.019 2.016 2.013 2.010 2.
Page 121 and 122:
ρυθμό 4 C.min -1 , έπειτ
Page 123 and 124:
ΜΕΛΕΤΗ ΤΟΥ ΦΑΙΝΟΜΕ
Page 125 and 126:
Νέοι Εξαφερίτες Ba µ
Page 127 and 128:
Crystal Structure of a new Supramol
Page 129 and 130:
Magnetic Phase Transition in Synthe
Page 131 and 132:
Συσχέτιση πλαστική
Page 133 and 134:
Μετασχηματισμοί φά
Page 135 and 136:
Μελέτη της Επίδρασ
Page 137 and 138:
Resonant Spin Transfer Torque in Do
Page 139 and 140:
3 η Προφορική Συνεδ
Page 141 and 142:
technology, and e-beam lithography.
Page 143 and 144:
ecause it reduces the calculation o
Page 145 and 146:
Υπολογισμός Υψηλής
Page 147 and 148:
The thermodynamic average is obtain
Page 149 and 150:
ΑΠΟΤΕΛΕΣΜΑΤΑ Στην
Page 151 and 152:
προερχόµενη είτε α
Page 153 and 154:
Combining Magnetism and Ferroelectr
Page 155 and 156:
υµένια LCMO/STO (100) πολ
Page 157 and 158:
Our scheme is illustrated in Fig. 1
Page 159 and 160:
[6] . Η μελέτη του υλι
Page 161 and 162:
τα πειραµατικά µας
Page 163 and 164:
συµπύκνωµα. Αυτό επ
Page 165 and 166:
και αναδεικνύει τρ
Page 167 and 168:
P P P P P power P copolymers P and
Page 169 and 170:
Αυτο-οργάνωση και Μ
Page 171 and 172:
Viscoelastic Response of Micelles w
Page 173 and 174:
Διηλεκτρική απόκρι
Page 175 and 176:
Light - induced Reversible Hydrophi
Page 177 and 178:
Οι παραπάνω τρεις κ
Page 179 and 180:
AP-PH (a.u.) 0.4 0.3 0.2 0.1 0.0 0
Page 181 and 182:
Synthesis of Polymer Brushes onto I
Page 183 and 184:
Conformational Properties of Dendri
Page 185 and 186:
Structure and Dynamics of Branched
Page 187 and 188:
∆οµή και ∆υναµική
Page 189 and 190:
Επίδραση της Τοπολ
Page 191 and 192:
(α) (β) Σχήμα 2: (α) Απε
Page 193 and 194:
Figure 3. Generation 4 PAMAM-H 2 O
Page 195 and 196:
Από όλα τα παραπάνω
Page 197 and 198:
Το PHEGMA είναι άμορφο
Page 199 and 200:
PS HAuCl 4 P2VP Ion loading PSP2VP
Page 201 and 202:
The nonlinear optical response of A
Page 203 and 204:
νανοσωµατίδια. Όπω
Page 205 and 206:
Bioactive Glass/Nanodiamonds system
Page 207 and 208:
Energy Loss Rates of Hot Electrons
Page 209 and 210:
Σύνθεση και Χαρακτ
Page 211 and 212:
μπορεί να ερμηνευτ
Page 213 and 214:
Nανοσυνθέτα Εποξει
Page 215 and 216:
[1] S. Iijima, Nature 354, 56 (1991
Page 217 and 218:
Figure 3: GCMC calculations for und
Page 219 and 220:
μερών, εμφανίζοντα
Page 221 and 222:
1.0 Reflectance 1.1 1.0 0.9 0.8 0.7
Page 223 and 224:
στο συντελεστή διέ
Page 225 and 226:
¿ÔÖØÑÒØÓÐØÖÐÒÒÖÒ¸
Page 227 and 228:
Συναπόθεση Cr - Ni σε
Page 229 and 230:
Investigation of the Structural, Mo
Page 231 and 232:
Modification of Perlite Cementitiou
Page 233 and 234:
Templated Sol-Gel Synthesis Of TiO
Page 235 and 236:
Παρασκευή Υμενίων
Page 237 and 238:
Preparation of YSZ Solid Electrolyt
Page 239 and 240:
Σύνθεση, Ανισοτροπ
Page 241 and 242:
Μελέτη ανθρώπινων
Page 243 and 244:
Local Coordination of Zn and Fe in
Page 245 and 246:
Επίδραση της Προσθ
Page 247 and 248:
Αλκαλική Σύνθεση κ
Page 249 and 250:
Μηχανικές Iδιότητε
Page 251 and 252:
The Influence of Thermal Aging on t
Page 253 and 254:
Modeling and quantitative phase ana
Page 255 and 256:
Συμβολή στη Συντήρ
Page 257 and 258:
Κρυσταλλική Συµπερ
Page 259 and 260:
Σύνθεση Στερεών ∆ι
Page 261 and 262:
Fabrication and Characterization of
Page 263 and 264:
∆ιερεύνηση δυνατό
Page 265 and 266:
Συγκριτική αξιολόγ
Page 267 and 268:
6 η Προφορική Συνεδ
Page 269 and 270:
Ηλεκτρομαγνητική Α
Page 271 and 272:
Φασματοσκοπική Μελ
Page 273 and 274:
Thermal and Electrical Properties o
Page 275 and 276:
Structure, Mechanical, and Optoelec
Page 277 and 278:
Designing Nanoporous Materials for
Page 279 and 280:
This program was developed to serve
Page 281 and 282:
Νέα Αυτό-οργανούμε
Page 283 and 284:
A Physical Model to Interpret the E
Page 285 and 286:
FIR study of Ag x (As 33 S 33 Se 33
Page 287 and 288:
Mελέτη Μεικτών Γυαλ
Page 289 and 290:
The Structural Role of Fe and Zn in
Page 291 and 292:
ΕΥΡΕΤΗΡΙΟ ΣΥΓΓΡΑΦΕ
Page 293 and 294:
Κομπίτσας Μ…………
Page 295 and 296:
ΕΥΡΕΤΗΡΙΟ ΣΥΓΓΡΑΦΕ
Page 297:
W Watson I.M………………4 Weg
show all

xxiii ÏÎ±Î½ÎµÎ»Î»Î·Î½Î¹Î¿ ÏÏ Î½ÎµÎ´ÏÎ¹Î¿ ÏÏ ÏÎ¹ÎºÎ·Ï ÏÏÎµÏÎµÎ±Ï ÎºÎ±ÏÎ±ÏÏÎ±ÏÎ·Ï & ÎµÏÎ¹ÏÏÎ·Î¼Î·Ï ...

Create successful ePaper yourself

Delete template?

Save as template?

xxiii ÏÎ±Î½ÎµÎ»Î»Î·Î½Î¹Î¿ ÏÏÎ½ÎµÎ´ÏÎ¹Î¿ ÏÏÏÎ¹ÎºÎ·Ï ÏÏÎµÏÎµÎ±Ï ÎºÎ±ÏÎ±ÏÏÎ±ÏÎ·Ï & ÎµÏÎ¹ÏÏÎ·Î¼Î·Ï ...