کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7969162 | 1514346 | 2018 | 22 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structural, optical and gas sensing properties of vertically well-aligned ZnO nanowires grown on graphene/Si substrate by thermal evaporation method
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We report catalyst-free vertical growth of high-density ZnO nanowire (NW) arrays on Si substrate with a graphene buffer layer by thermal evaporation method. Structural, surface morphology, chemical composition and optical properties of ZnO NWs were studied by Field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and Raman spectroscopy. The results indicate that the grown ZnO NWs are single-crystalline and exhibit the hexagonal wurtzite crystal structure with a preferred orientation along the [0001] direction; all of the ZnO NWs vertically grow on the graphene/Si substrate. The majority of the as-grown NWs have diameters in the range of 250-300â¯nm and length up to several tens of micrometers, whereas a small portion of NWs have a diameter of approximately of 9-12â¯nm. Room temperature PL spectrum of the ZnO NWs exhibits a sharp and strong ultraviolet emission at 380â¯nm and a weak visible emission at around 516â¯nm. The role of graphene buffer layer in the vertical-aligned ZnO NW arrays growth and its improved optical properties is demonstrated. Importantly, the gas sensor based on these ZnO NWs exhibits high sensitivity and rapid response/recovery characteristics to NO2 gas at 200â¯Â°C, and can detect NO2 concentration as low as 2, 6 and 10â¯ppm. The excellent sensing performance is mainly due to the combination of the large specific surface area and the presence of oxygen-vacancies at the surface of ZnO NWs, together with the creation of p-n heterojunctions between n-type ZnO NW and p-type graphene. Such a ZnO NW/graphene structure is very promising for various applications, such as photonic, optoelectronic and sensor devices. In addition, the possible growth mechanism and the NO2 sensing gas mechanism of the ZnO NWs-graphene structure have been discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Characterization - Volume 141, July 2018, Pages 296-317
Journal: Materials Characterization - Volume 141, July 2018, Pages 296-317
نویسندگان
Tran Van Khai, Le Van Thu, La Thi Thai Ha, Vu Minh Thanh, Tran Dai Lam,