http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Ekmel (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Engin Arslan,Mustafa K. Ozturk,Suleyman Ozcelik,Ekmel Ozbay 한국물리학회 2009 Current Applied Physics Vol.9 No.3
In the present paper, the effects of nitridation on the quality of GaN epitaxial films grown on Si(111) substrates by metal–organic chemical vapor phase deposition (MOCVD) are discussed. A series of GaN layers were grown on Si(111) under various conditions and characterized by Nomarski microscopy (NM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD), and room temperature (RT) photoluminescence (PL) measurements. Firstly, we optimized LT-AlN/HT-AlN/Si(111) templates and graded AlGaN intermediate layers thicknesses. In order to prevent stress relaxation, step-graded AlGaN layers were introduced along with a crack-free GaN layer of thickness exceeding 2.2 ㎛. Secondly, the effect of in situ substrate nitridation and the insertion of an SixNy intermediate layer on the GaN crystalline quality was investigated. Our measurements show that the nitridation position greatly influences the surface morphology and PL and XRD spectra of GaN grown atop the SixNy layer. The X-ray diffraction and PL measurements results confirmed that the single-crystalline wurtzite GaN was successfully grown in samples A (without SixNy layer) and B (with SixNy layer on Si(111)). The resulting GaN film surfaces were flat, mirror-like, and crack-free. The full-width-at-half maximum (FWHM) of the X-ray rocking curve for (0002) diffraction from the GaN epilayer of the sample B in ω-scan was 492 arcsec. The PL spectrum at room temperature showed that the GaN epilayer had a light emission at a wavelength of 365 nm with a FWHM of 6.6 nm (33.2 meV). In sample B, the insertion of a SixNy intermediate layer significantly improved the optical and structural properties. In sample C (with SixNy layer on Al0.11Ga0.89N interlayer). The in situ depositing of the, however, we did not obtain any improvements in the optical or structural properties. In the present paper, the effects of nitridation on the quality of GaN epitaxial films grown on Si(111) substrates by metal–organic chemical vapor phase deposition (MOCVD) are discussed. A series of GaN layers were grown on Si(111) under various conditions and characterized by Nomarski microscopy (NM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD), and room temperature (RT) photoluminescence (PL) measurements. Firstly, we optimized LT-AlN/HT-AlN/Si(111) templates and graded AlGaN intermediate layers thicknesses. In order to prevent stress relaxation, step-graded AlGaN layers were introduced along with a crack-free GaN layer of thickness exceeding 2.2 ㎛. Secondly, the effect of in situ substrate nitridation and the insertion of an SixNy intermediate layer on the GaN crystalline quality was investigated. Our measurements show that the nitridation position greatly influences the surface morphology and PL and XRD spectra of GaN grown atop the SixNy layer. The X-ray diffraction and PL measurements results confirmed that the single-crystalline wurtzite GaN was successfully grown in samples A (without SixNy layer) and B (with SixNy layer on Si(111)). The resulting GaN film surfaces were flat, mirror-like, and crack-free. The full-width-at-half maximum (FWHM) of the X-ray rocking curve for (0002) diffraction from the GaN epilayer of the sample B in ω-scan was 492 arcsec. The PL spectrum at room temperature showed that the GaN epilayer had a light emission at a wavelength of 365 nm with a FWHM of 6.6 nm (33.2 meV). In sample B, the insertion of a SixNy intermediate layer significantly improved the optical and structural properties. In sample C (with SixNy layer on Al0.11Ga0.89N interlayer). The in situ depositing of the, however, we did not obtain any improvements in the optical or structural properties.
-
-
Ozer, Zafer,Kurtoglu, Cem,Mamedov, Amirullah M.,Ozbay, Ekmel Korean Academy of Dental Science 2015 Journal of korean dental science Vol.8 No.1
Purpose: To investigate the influence of crown margin design on the stress distribution and to localize critical sites in maxillary canine under functional loading by using three dimensional finite element analysis. Materials and Methods: The bite force of 100 N, 150 N, and 200 N was applied with an angulation of $45^{\circ}$ to the longitudinal axis of tooth. Six models were restored with IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) with a different margin design. With lingual ledge and various thicknesses, three different core ceramics were designed in each model. Result: In the core ceramic, the maximum tensile stresses were found at the labiocervical region. In the veneering ceramic the maximum tensile stresses were found at the area where the force was applied in all models. Conclusion: Shoulder and chamfer margin types are acceptable for all-ceramic rehabilitations. A ledge on the core ceramic at cervical region may affect the strength of all-ceramic crowns.
-
SiC Substrate Effects on Electron Transport in the Epitaxial Graphene Layer
Engin Arslan,Semih Çakmakyapan,Özgür Kazar,Serkan Bütün,Sefer Bora Li esivdin,Neval A. Cinel,Gülay Ertas,Sükrü Ardal,Engin T ras,Jawad-ul-Hassan,E. Janzén,Ekmel Özbay 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.2
Hall effect measurements on epitaxial graphene (EG) on SiC substrate have been carried out as a function of temperature. The mobility and concentration of electrons within the two-dimensional electron gas (2DEG) at the EG layers and within the underlying SiC substrate are readily separated and characterized by the simple parallel conduction extraction method (SPCEM). Two electron carriers are identified in the EG/SiC sample: one highmobility carrier (3493 cm2/Vs at 300 K) and one low-mobility carrier (1115 cm2/Vs at 300 K). The high mobility carrier can be assigned to the graphene layers. The second carrier has been assigned to the SiC substrate.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
