Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Other Erratum To: Mbe-Grown Cdte Layers on Gaas With In-Assisted Thermal Deoxidation(Springer Verlag, 2016) Arı, Ozan; Bilgilisoy, Elif; Özçeri, Elif; Selamet, YusufArticle Citation - WoS: 6Citation - Scopus: 5Mbe-Grown Cdte Layers on Gaas With In-Assisted Thermal Deoxidation(Springer Verlag, 2016) Arı, Ozan; Bilgilisoy, Elif; Özçeri, Elif; Selamet, YusufMolecular 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.Article Citation - WoS: 3Citation - Scopus: 3Growth and Characterization of Cdte Absorbers on Gaas by Mbe for High Concentration Pv Solar Cells(John Wiley and Sons Inc., 2015) Arı, Ozan; Polat, Mustafa; Karakaya, Merve; Selamet, YusufCdTe based II-VI absorbers are promising candidates for high concentration PV solar cells with an ideal band gap for AM1.5 solar radiation. In this study, we propose single crystal CdTe absorbers grown on GaAs substrates with a molecular beam epitaxy (MBE) which is a clean deposition technology. We show that high quality CdTe absorber layers can be grown with full width half maximum of X-ray diffraction rocking curves (XRD RC) as low as 227 arc-seconds with 0.5% thickness uniformity that a 2 μm layer is capable of absorbing 99% of AM1.5 solar radiation. Bandgap of the CdTe absorber is found as 1.483 eV from spetroscopic ellipsometry (SE) measurements. Also, high absorption coefficient is calculated from the results, which is ∼5 x 105cm-1 in solar radiation spectrum.