论文标题
在溅射锡$ _ {\ boldsymbol {x}} $上生长的gan纳米线的辐射效率增强：表面电场的效果
Enhanced radiative efficiency in GaN nanowires grown on sputtered TiN$_{\boldsymbol{x}}$: effects of surface electric fields
论文作者
论文摘要
分子束外延生长的gan纳米线通常患有主要的非辐射重组，据信这起源于点缺陷。为了抑制这些缺陷的形成，我们通过使用热稳定的锡$ _x $ _x $/al $ _2 $ _3 $ _3 $ substress探索了高达915 $°C $的GAN纳米线的合成。这些样品确实表现出绑定的激子衰变时间，即接近用于最先进的大量gan的衰减时间。但是，衰减时间与生长温度无关，而与纳米线直径相关。衰减时间对直径的逆依赖性表明，GAN纳米线中的非辐射过程不受缺陷密度的控制，而是由radial电场中的激子的场电离控制，由表面带弯曲引起。我们提出了一种统一的机制，该机制是对任意直径的GAN纳米线中非辐射重组的统一机制。
GaN nanowires grown by molecular beam epitaxy generally suffer from dominant nonradiative recombination, which is believed to originate from point defects. To suppress the formation of these defects, we explore the synthesis of GaN nanowires at temperatures up to 915 $°C$ enabled by the use of thermally stable TiN$_x$/Al$_2$O$_3$ substrates. These samples exhibit indeed bound exciton decay times approaching those measured for state-of-the-art bulk GaN. However, the decay time is not correlated with the growth temperature, but rather with the nanowire diameter. The inverse dependence of the decay time on diameter suggests that the nonradiative process in GaN nanowires is not controlled by the defect density, but by the field ionization of excitons in the radial electric field caused by surface band bending. We propose a unified mechanism accounting for nonradiative recombination in GaN nanowires of arbitrary diameter.
