Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095, USA.
Nanoscale. 2017 Jun 22;9(24):8220-8228. doi: 10.1039/c7nr00948h.
We present the first demonstration of arsenic-rich InAsP (0 ≤ x ≤ 0.33) nanowire arrays grown on InP (111)B substrates by catalyst-free selective-area metal-organic chemical vapor deposition. It is shown that by introducing a thin InAs seeding layer prior to the growth of the nanowire, an extremely high vertical yield is achieved by eliminating rotational twins between (111)A and (111)B crystal orientations. InAsP nanowire arrays show strong emission of photoluminescence (PL) at room temperature, suggesting a significant reduction of surface state density compared with InAs nanowires. The phosphorus composition deduced from the PL peak energy is verified by energy-dispersive X-ray spectroscopy. The growth temperature shows a strong impact on the aspect ratio of InAsP nanowires with different phosphorus compositions. In addition, no PL emission is observed from nanowires grown with arsenic overpressure, likely due to an exchange of phosphorus with arsenic atoms at the surface which results in an increase in the surface state density. These results provide a path for the growth of heterojunctions based on As-rich InAsP for nanoscale short-wavelength infrared and mid-wavelength infrared optical devices.
我们首次展示了在 InP（111）B 衬底上通过无催化剂选择性区域金属有机化学气相沉积生长的富砷 InAsP（0≤x≤0.33）纳米线阵列。结果表明，通过在纳米线生长前引入一层薄的 InAs 种晶层，可以消除（111）A 和（111）B 晶向之间的旋转孪晶，从而实现极高的垂直产率。InAsP 纳米线阵列在室温下表现出很强的光致发光（PL）发射，表明与 InAs 纳米线相比，表面态密度有显著降低。PL 峰能量推断出的磷成分通过能谱得到验证。生长温度对不同磷成分的 InAsP 纳米线的纵横比有很强的影响。此外，在砷过压下生长的纳米线没有观察到 PL 发射，这可能是由于表面的磷与砷原子发生交换，导致表面态密度增加。这些结果为基于富砷 InAsP 的纳米尺度短波长红外和中波长红外光器件的异质结生长提供了一条途径。
