Center for Nanoscale Photonics and Spintronics, University of Michigan, Ann Arbor, Michigan 48109-2122, USA.
Nano Lett. 2010 Sep 8;10(9):3355-9. doi: 10.1021/nl101027x.
Catalyst-free growth of (In)GaN nanowires on (001) silicon substrate by plasma-assisted molecular beam epitaxy is demonstrated. The nanowires with diameter ranging from 10 to 50 nm have a density of 1-2 x 10(11) cm(-2). P- and n-type doping of the nanowires is achieved with Mg and Si dopant species, respectively. Structural characterization by high-resolution transmission electron microscopy (HRTEM) indicates that the nanowires are relatively defect-free. The peak emission wavelength of InGaN nanowires can be tuned from ultraviolet to red by varying the In composition in the alloy and "white" emission is obtained in nanowires where the In composition is varied continuously during growth. The internal quantum efficiency varies from 20-35%. Radiative and nonradiative lifetimes of 5.4 and 1.4 ns, respectively, are obtained from time-resolved photoluminescence measurements at room temperature for InGaN nanowires emitting at lambda = 490 nm. Green- and white-emitting planar LEDs have been fabricated and characterized. The electroluminescence from these devices exhibits negligible quantum confined Stark effect or band-tail filling effect.
采用等离子体辅助分子束外延法在（001）硅衬底上无催化剂生长（In）GaN 纳米线。纳米线的直径在 10 到 50nm 之间，密度为 1-2×10(11)cm(-2)。分别用 Mg 和 Si 掺杂剂实现了纳米线的 p 型和 n 型掺杂。高分辨率透射电子显微镜（HRTEM）的结构表征表明纳米线几乎没有缺陷。通过改变合金中的 In 成分，可以将 InGaN 纳米线的峰值发射波长从紫外调谐到红，并且在生长过程中连续改变 In 成分可以获得“白色”发射。内部量子效率为 20-35%。通过室温下 490nm 发射的 InGaN 纳米线的时间分辨光致发光测量，得到辐射和非辐射寿命分别为 5.4ns 和 1.4ns。已制备并表征了绿光和白光发射的平面 LED。这些器件的电致发光表现出可忽略的量子限制斯塔克效应或带尾填充效应。
