کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10676268 | 1011292 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effects of different modified underlayer surfaces on growth and optical properties of InGaN quantum dots
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سطوح، پوششها و فیلمها
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Effects of different modified underlayer surfaces on growth and optical properties of InGaN quantum dots Effects of different modified underlayer surfaces on growth and optical properties of InGaN quantum dots](/preview/png/10676268.png)
چکیده انگلیسی
InGaN/GaN quantum dots were grown on the sapphire (0Â 0Â 0Â 1) substrate in a metalorganic chemical vapor deposition system. The morphologies of QDs deposited on different modified underlayer (GaN) surfaces, including naturally as grown, Ga-mediated, In-mediated, and air-passivated ones, were investigated by atomic force microscopy (AFM). Photoluminescence (PL) method is used to evaluate optical properties. It is shown that InGaN QDs can form directly on the natural GaN layer. However, both the size and distribution show obvious inhomogeneities. Such a heavy fluctuation in size leads to double peaks for QDs with short growth time, and broad peaks for QDs with long growth time in their low-temperature PL spectra. QDs grown on the Ga-mediated GaN underlayer tends to coalesce. Distinct transform takes place from 3D to 2D growth on the In-mediated ones, and thus the formation of QDs is prohibited. Those results clarify Ga and In's surfactant behavior. When the GaN underlayer is passivated in the air, and together with an additional low-temperature-grown seeding layer, however, the island growth mode is enhanced. Subsequently, grown InGaN QDs are characterized by a relatively high density and an improved Gaussian-like distribution in size. Short surface diffusion length at low growth temperature accounts for that result. It is concluded that reduced temperature favors QD's 3D growth and surface passivation can provide another promising way to obtain high-density QDs that especially suits MOCVD system.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vacuum - Volume 77, Issue 3, 18 February 2005, Pages 307-314
Journal: Vacuum - Volume 77, Issue 3, 18 February 2005, Pages 307-314
نویسندگان
Xiuxun Han, Jiemin Li, Jiejun Wu, Xiaohui Wang, Dabing Li, Xianglin Liu, Peide Han, Qinsheng Zhu, Zhanguo Wang,