Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4719

Browse

Filters

20163

Settings

Author: search.filters.author.Bilgilisoy, Elif

Search Results

Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Surface Roughness Estimation of Mbe Grown Cdte/Gaas(211)b by Ex-Situ Spectroscopic Ellipsometry
    (American Institute of Physics, 2016) Karakaya, Merve; Bilgilisoy, Elif; Arı, Ozan; Selamet, Yusuf; Bilgilisoy, Elif; Selamet, Yusuf; Karakaya, Merve; 01. Izmir Institute of Technology; 04.05. Department of Pyhsics; 04. Faculty of Science
    Spectroscopic ellipsometry (SE) ranging from 1.24 eV to 5.05 eV is used to obtain the film thickness and optical properties of high index (211) CdTe films. A three-layer optical model (oxide/CdTe/GaAs) was chosen for the ex-situ ellipsometric data analysis. Surface roughness cannot be determined by the optical model if oxide is included. We show that roughness can be accurately estimated, without any optical model, by utilizing the correlation between SE data (namely the imaginary part of the dielectric function, <ϵ2 > or phase angle, ψ) and atomic force microscopy (AFM) roughness. <ϵ2 > and ψ values at 3.31 eV, which corresponds to E1 critical transition energy of CdTe band structure, are chosen for the correlation since E1 gives higher resolution than the other critical transition energies. On the other hand, due to the anisotropic characteristic of (211) oriented CdTe surfaces, SE data (<ϵ2 > and ψ) shows varieties for different azimuthal angle measurements. For this reason, in order to estimate the surface roughness by considering these correlations, it is shown that SE measurements need to be taken at the same surface azimuthal angle. Estimating surface roughness in this manner is an accurate way to eliminate cumbersome surface roughness measurement by AFM.
  • Other
    Erratum To: Mbe-Grown Cdte Layers on Gaas With In-Assisted Thermal Deoxidation
    (Springer Verlag, 2016) Arı, Ozan; Bilgilisoy, Elif; Selamet, Yusuf; Selamet, Yusuf; Arı, Ozan; Bilgilisoy, Elif; 01. Izmir Institute of Technology; 04.05. Department of Pyhsics; 04. Faculty of Science
  • Article
    Citation - WoS: 6
    Citation - Scopus: 5
    Mbe-Grown Cdte Layers on Gaas With In-Assisted Thermal Deoxidation
    (Springer Verlag, 2016) Arı, Ozan; Bilgilisoy, Elif; Selamet, Yusuf; Selamet, Yusuf; Arı, Ozan; Bilgilisoy, Elif; 01. Izmir Institute of Technology; 04.05. Department of Pyhsics; 04. Faculty of Science
    Molecular beam epitaxy (MBE) growth of thin (∼2 μm) CdTe layers characterized by high crystal quality and low defect density on lattice mismatched substrates, such as GaAs and Si, has thus far been difficult to achieve. In this work, we report the effects of in situ thermal deoxidation under In and As4 overpressure prior to the CdTe growth on epiready GaAs(211)B wafers, aiming to enhance CdTe crystal quality. Thermally deoxidized GaAs samples were analyzed using in situ reflection high energy electron diffraction, along with ex situ x-ray photo-electron spectroscopy (XPS) and atomic force microscopy. MBE-grown CdTe layers were characterized using x-ray diffraction (XRD) and Everson-type wet chemical defect decoration etching. We found that In-assisted desorption allowed for easier surface preparation and resulted in a smoother surface compared to As-assisted surface preparation. By applying In-assisted thermal deoxidation to GaAs substrates prior to the CdTe growth, we have obtained single crystal CdTe films with a CdTe(422) XRD rocking curve with a full-width half-maximum value of 130.8 arc-s and etch pit density of 4 × 106 cm−2 for 2.54 μm thickness. We confirmed, by XPS analysis, no In contamination on the thermally deoxidized surface.