Optimisation of the parameters of an extended defect model applied to non-amorphizing implants

In this paper, we present the optimisation of the parameters of a physical model of the kinetics of extended defects and applied the model with the optimised parameters to non-amorphizing implants. The model describes the small clusters, the {113} defects and the dislocation loops. In the first part, we determine the formation energies of the small clusters, the fault energy of the {113} defects, their Burgers vector and the self-diffusivity of silicon using TEM measurements and extractions of the supersaturation from the spreading of boron marker layers in low-dose implanted silicon. The improvements of the simulations are presented for the fitted experiments and for other wafers annealed at intermediate temperatures. In the second part, we increase the dose and energy of the non-amorphizing implant, leading to the transformation of {113} defects into dislocation loops. The predictions obtained with the optimised model are shown to be in agreement with the measurements. (c) 2005 Elsevier B.V. All rights reserved

Penerapan Model Pembelajaran Kooperatif Tipe STAD untuk Meningkatkan Minat Belajar Peserta Didik Kelas XI IPA. 1 SMA Negeri 1 Sa’dan Balusu terhadap Mata Pelajaran Kimia

ABSTRAKPengajaran Kimia di SMA Negeri 1 Sa’dan Balusu sampai saat ini belum bisa dikatakan berhasil. Kenyataan ini didukung oleh ketuntasan belajar peserta didik masih jauh dari yang diharapkan. Adanya sebagian guru kimia yang di dalam mengajar hanya dengan metode ceramah tanpa melibatkan peserta didik untuk aktif di dalamnya, semakin menambah kecenderungan peserta didik bahwa kimia itu membosankan. Dengan memperhatikan kesenjangan yang ada dan untuk mendapatkan pemecahan dari permasalahan tersebut, maka dilakukan Penelitian Tindakan Kelas (PTK) dengan metode pembelajaran kooperatif tipe STAD dalam pembelajaran konsep Termokimia. PTK ini dilakukan dalam dua siklus pembelajaran, dimana masing-masing siklus terdiri dari 1. Perencanaan; 2. Pelaksanaan; 3. Pengamatan; 4. Refleksi. Subyek penelitian ini adalah peserta didik kelas XI IPA. 1 SMA Negeri 1 Sa’dan Balusu. Hasil penelitian ini menunjukkan bahwa terdapat peningkatan minat belajar peserta didik.Kata kunci: Kooperatif, Minat Belajar, Chemistry ABSTRACTChemistry Teaching at SMA Negeri 1 Sa'dan Balusu has not been successful yet. This fact is supported by the completeness of student learning is still far from expected. The existence of some chemistry teachers who teach only speaking method without the involvement of students to be active in it, increasing the student's tendency that chemistry is boring. By considering the existing gap and to get the solution of the problem, the Classroom Action Research with STAD type cooperative learning method in learning Thermochemical concept was done. This Classroom Action Research was conducted in two learning cycles, each cycle consisting of 1. Planning; 2. Implementation; 3. Observations; 4. Reflection. The subjects of this study were students of class XI IPA. 1 at SMA Negeri 1 Sa'dan Balusu. The results of this study indicate that there was enhancement of  student learning interest.Keywords: Cooperative, Learning interest, Chemistr

2D Time-frequency interference modelling using stochastic geometry for performance evaluation in Low-Power Wide-Area Networks

In wireless networks, interferences between trans- missions are modelled either in time or frequency domain. In this article, we jointly analyze interferences in the time- frequency domain using a stochastic geometry model assuming the total time-frequency resources to be a two-dimensional plane and transmissions from Internet of Things (IoT) devices time- frequency patterns on this plane. To evaluate the interference, we quantify the overlap between the information packets: provided that the overlap is not too strong, the packets are not necessarily lost due to capture effect. This flexible model can be used for multiple medium access scenarios and is especially adapted to the random time-frequency access schemes used in Low-Power Wide-Area Networks (LPWANs). By characterizing the outage probability and throughput, our approach permits to evaluate the performance of two representative LPWA technologies Sigfox{\textsuperscript \textregistered} and LoRaWA{\textsuperscript \textregistered}

Solid phase epitaxy amorphous silicon re-growth: some insight from empirical molecular dynamics simulation

The modelling of interface migration and the associated diffusion mechanisms at the nanoscale level is a challenging issue. For many technological applications ranging from nanoelectronic devices to solar cells, more knowledge of the mechanisms governing the migration of the silicon amorphous/crystalline interface and dopant diffusion during solid phase epitaxy is needed. In this work, silicon recrystallisation in the framework of solid phase epitaxy and the influence on orientation effects have been investigated at the atomic level using empirical molecular dynamics simulations. The morphology and the migration process of the interface has been observed to be highly dependent on the original inter-facial atomic structure. The [100] interface migration is a quasi-planar ideal process whereas the cases [110] and [111] are much more complex with a more diffuse interface. For [110], the interface migration corresponds to the formation and dissolution of nanofacets whereas for [111] a defective based bilayer reordering is the dominant re-growth process. The study of the interface velocity migration in the ideal case of defect free re-growth reveals no difference between [100] and [110] and a decrease by a mean factor of 1.43 for the case [111]. Finally, the influence of boron atoms in the amorphous part on the interface migration velocity is also investigated in the case of [100] orientation

Plasmonic behavior of III-V semiconductors in far-infrared and terahertz range

Background: In this article, III-V semiconductors are proposed as materials for far-infrared and terahertz plasmonic applications. We suggest criteria to estimate appropriate spectral range for each material including tuning by fine doping and magnetic field. Methods: Several single-crystal wafer samples (n, p-doped GaAs, n-doped InP, and n, p-doped and undoped InSb) are characterized using reflectivity measurement and their optical properties are described using the Drude-Lorentz model, including magneto-optical anisotropy. Results: The optical parameters of III-V semiconductors are presented. Moreover, strong magnetic modulation of permittivity was demonstrated on the undoped InSb crystal wafer in the terahertz spectral range. Description of this effect is presented and the obtained parameters are compared with a Hall effect measurement. Conclusion: Analyzing the phonon/free carrier contribution to the permittivity of the samples shows their possible use as plasmonic materials; the surface plasmon properties of semiconductors in the THz range resemble those of noble metals in the visible and near infrared range and their properties are tunable by either doping or magnetic field.Web of Science13art. no. 1

High-resolution THz gain measurements in optically pumped ammonia

This study is aimed at the evaluation of THz gain properties in an optically pumped NH3 gas. NH3 molecules undergo rotational-vibrational excitation by mid-infrared (MIR) optical pumping provided by a MIR quantum cascade laser (QCL) which enables precise tuning to the NH3 infrared transition around 10.3 mu m. Pure inversion transitions, (J = 3, K = 3) at 1.073 THz and (J = 4, K = 4) at 1.083 THz were selected. The THz measurements were performed using a THz frequency multiplier chain. The results show line profiles with and without optical pumping at different NH3 pressures, and with different MIR tuning. The highest gain at room temperature under the best conditions obtained during single pass on the (3,3) line was 10.1 dBxm(-1) at 26 mu bar with a pumping power of 40 mW. The (4,4) line showed lower gain of 6.4 dBxm(-1) at 34 mu bar with a pumping power of 62 mW. To our knowledge these THz gains are the highest measured in a continuous-wave MIR pumped gas.Web of Science2616212482124