Optical properties of SiGe single crystals grown by liquid phase diffusion

In this article, we present measurements for the pseudo-optical functions of germanium-rich SixGe1-x (0.000<x<0.100) single-crystals(grown by Liquid Phase Diffusion; LPD) using spectroscopic ellipsometry and photo reflectance techniques in the energy range of 1.72–3.20 eV. The E1 interband transition energies are obtained from numerically differentiated optical spectra for various crystal compositions. It was shown that the values of E1 interband transition energy determined by both the ellipsometric and photo reflectance measurements for germanium-rich SixGe1-x single-crystals are in agreement with those of bulk SiGe crystals reported in the literature[21–24].The interband transition energies are found to be in the range of 2.100 and 2.215 eV for the composition values of 0.000<x0.100. The surface morphology of the crystals assayed via atomic force microscopy shows fibrous surfaces with the average grain size of 250 nm. The measured root-mean-square (rms) roughness and maximum height are in the range of 3.78–5.40 and 32.42–67.84 nm, respectively, with increasing germanium composition

Vakumda buharlaştırma yöntemiyle hazırlanan Cu ve Au yüzeyleri üzerindeki ısısal Cu2O ince filmlerinin optik özellikleri

ABSTRACT OPTICAL PROPERTIES OF THIN THERMAL Cu20 FILMS ON VACUUM EVAPORATED Cu AND Au SURFACES DERİN, Hüseyin Thesis of Ph. D. in Science Supervisor : Prof. Dr. Kayhan KANTARLI September 1997, 128 pages In this work, the optical properties of thin Cu20 films in the Cu20/Cu and Cu20/Au structures obtained by the vacuum evaporation technique followed by the thermal oxidation in air, have been investigated using the ellipsometric and spectrophotometric methods. From the investigation of oxidation kinetics, it was found that the oxide growth in the range of 80 - 125°C exhibits a parabolic behaviour. It was shown that the growth of the thermal oxide film on Cu surface can be observed by means of both the ellipsometric parameters and the reflectance measurements. Exact optical characterization in the visible range of the thin Cu20 films grown at 125°C were carried out through the analysis of the ellipsometric measurements taken at two different angle of incidences. It was found that the optical constants do not show an important change with the thickness of the films. The forbidden band gap, determined from the spectral behaviour of the absorption coefficient of Cu20, is consistent with the values reported in the literature. By comparing the results obtained for the Cu20/Cu and Cu20/Au structures, it was shown that the possible volume diffusion and roughness in the Cu - Cu20 interface do not affect the optical characterization, performed by the ellipsometric method. Keywords: Thin films, optical properties, oxidation, ellipsometry.IV ÖZET VAKUMDA BUHARLAŞTIRMA YÖNTEMİYLE HAZIRLANAN Cu ve Au YÜZEYLERİ ÜZERİNDEKİ ISISAL Cu20 İNCE FİLMLERİNİN OPTİK ÖZELLİKLERİ DERİN, Hüseyin Doktora Tezi, Fizik Bölümü Tez Yöneticisi: Prof. Dr. Kayhan KANTARLI Eylül 1997, 128 sayfa Bu çalışmada vakumda buharlaştırma tekniği ve havada ısısal oksidasyon işlemiyle elde edilen Cu20/Cu ve Cu20/Au yapılarındaki Cu20 ince filmlerinin optik özellikleri elipsometrik ve spektrofotometrik yöntemlerle incelendi. Oksidasyon kinetiğinin incelenmesinden 80 - 125°C bölgesindeki oksit büyümesinin parabolik bir davranış gösterdiği bulundu. Cu yüzeyi üzerindeki ısısal oksit filmi büyümesinin hem elipsometrik parametreler ve hemde reflektans ölçümleriyle izlenebileceği gösterildi. 125°C de büyütülen Cu20 ince filrmerirıin görünür bölgedeki tam optiksel karakterizasyonu, farklı iki gelme açısında alman elipsometrik ölçümlerin analiziyle yapıldı. Optik sabitlerin film kalınlığı ile önemli bir değişim göstermediği bulundu. Cu20 'in absorpsiyon katsayısının spektral davranışından belirlenen yasak band genişliği değerinin literatürdeki değerlerle uyumlu olduğu gösterildi. Cu20/Cu ve Cu20/Au yapılan için elde edilen sonuçlar karşılaştırılarak, Cu - Cu20 arayüzeyindeki olası hacım difuzyonu ve pürüzlülüğün, elipsometrik yöntemle yapılan optiksel karakterizasyonu etkilemediği gösterildi

Optical properties of Si x Ge 1Àx single crystals grown by liquid phase diffusion

a b s t r a c t In this article, we present measurements for the pseudo-optical functions of germanium-rich Si x Ge 1Àx (0.000rxr0.100) single-crystals (grown by Liquid Phase Diffusion; LPD) using spectroscopic ellipsometry and photoreflectance techniques in the energy range of 1.72-3.20 eV. The E 1 interband transition energies are obtained from numerically differentiated optical spectra for various crystal compositions. It was shown that the values of E 1 interband transition energy determined by both the ellipsometric and photoreflectance measurements for germanium-rich Si x Ge 1Àx single-crystals are in agreement with those of bulk SiGe crystals reported in the literatur

Resource recovery as a sustainable perspective for the remediation of mining wastes: rehabilitation of the CMC mining waste site in Northern Cyprus

This paper highlights resource recovery and stabilization as the novel approach adopted in the rehabilitation strategy of the abandoned copper mine site (CMC mine) located in Northern Cyprus, recognized as a source of chronic pollution problems. The site holds 9.5 million tons of tailings stored in poorly equipped ponds. The waste contains pyrite and chalcopyrite undergoing slow oxidation this way, sulfide has been partly converted to sulfuric acid causing severe acid mine drainage problems. The rehabilitation strategy adopted the EU’s key principle of resource recovery, where all tailings would be processed for copper recovery and stabilized to further prevent the chemical mobility of heavy metals before final landfilling. A leaching-cementation process, with no chemical usage, except for lime stabilization after recovery, was designed for this purpose. The corresponding action plan entailed that all the waste material be processed in situ, in a zero waste environment. Accordingly, the remediation will be carried out in a sequential process involving emptying the ponds for resource recovery, preparing the necessary number of emptied ponds with sufficient holding capacity, as selected landfill sites in a way to secure and provide all necessary measures imposed by international regulations for containing and controlling hazardous wastes. Finally closure plans will be implemented for the rehabilitation of the mining site to reclaim full attributes of natural characteristics

A rare mass of palatine tonsils: Schwannoma

Tonsils schwannoma are benign tumors that the main symptoms difficulty swallowing and snoring, foreign body sensation, sore throat, and slow-growing. The aim of study is to describe the case of 34 years of old female who presented with a schawannoma in her left palatine tonsil of the tumor that were surgically removed transorally. There weren’t any complications like recurrence until postoperation one year