Coaxial InGaN Epitaxy Around GaN Nano-tubes: Tracing the Signs
نویسنده
چکیده
This work focuses on investigations of the luminescence properties of coaxial InGaN layers around single GaN nano-tubes on top of GaN micro-pyramids. The nano-tube structure was formed after the controlled desorption of ZnO nano-pillar templates during the coaxial GaN epitaxy. An intense and broad photoluminescence (PL) peak centered around 2.85 eV is attributed to transitions from a shallow donor or from the conduction band to a ZnGa acceptor level above the valence band edge. A thin layer near the area around the inner diameter of the nano-tube is believed to be heavily doped with Zn impurities. These are believed to hinder the luminescence from coaxial InGaN quantum wells (QWs) around the GaN nanotube. Comparing samples with and without QWs, where the thickness of the GaN tube wall before the QW growth was doubled, a clear indication of In incorporation in low temperature PL was observed via an intense peak around 3.1 eV. Moreover, as the temperature of the QW growth was changed from 830 C to 780 C, a shift of the peak corresponding to an increase in In incorporation from 3.5% to 7.5% was noticed.
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