Straight GaN nanowires (NWs) with diameters of 50 nm, lengths up to 10 μm and a hexagonal wurtzite crystal structure have been grown at 900°C on 0.5 nm Au/Si(001) via the reaction of Ga with NH3 and N2:H2, where the H2 content was varied between 10 and 100%. The growth of high-quality GaN NWs depends critically on the thickness of Au and Ga vapor pressure while no deposition occurs on plain Si(001). Increasing the H2 content leads to an increase in the growth rate, a reduction in the areal density of the GaN NWs and a suppression of the underlying amorphous (α)-like GaN layer which occurs without H2. The increase in growth rate with H2 content is a direct consequence of the reaction of Ga with H2 which leads to the formation of Ga hydride that reacts efficiently with NH3 at the top of the GaN NWs. Moreover, the reduction in the areal density of the GaN NWs and suppression of the α-like GaN layer is attributed to the reaction of H2 with Ga in the immediate vicinity of the Au NPs. Finally, the incorporation of H2 leads to a significant improvement in the near band edge photoluminescence through a suppression of the non-radiative recombination via surface states which become passivated not only via H2, but also via a reduction of O2-related defects.
展开▼
机译：通过Ga与NH3和N2：H2的反应，在900°C上于0.5 nm Au / Si（001）上生长了直径为50 nm，长度最大为10μm和六方纤锌矿晶体结构的GaN直线纳米线（NWs）。 ，其中H2含量在10％到100％之间变化。高质量GaN NW的生长关键取决于Au和Ga蒸气压的厚度，而在纯Si（001）上不会发生沉积。 H 2含量的增加导致生长速率的增加，GaN NW的面密度的减小以及在没有H 2的情况下对下面的无定形（α）状GaN层的抑制。随着H2含量的增加，生长速率的增加是Ga与H2反应的直接结果，这导致形成氢化镓Ga，氢化镓与GaN NWs顶部的NH3有效反应。此外，GaN NW的面密度的降低和α状GaN层的抑制归因于在Au NPs附近的H2与Ga的反应。最后，通过抑制经由表面状态的非辐射复合，H 2的掺入导致近带边缘光致发光的显着改善，所述表面状态不仅通过H 2钝化，而且通过减少与O 2有关的缺陷而钝化。
展开▼
