Rate-limiting mechanisms in high-temperature growth of catalyst-free InAs nanowires with large thermal stability
Rate-limiting mechanisms in high-temperature growth of catalyst-free InAs nanowires with large thermal stability
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DOI：
10.1088/0957-4484/23/23/235602
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发表时间：
2012-06-15
期刊：
影响因子：
3.5
通讯作者：
Koblmueller, G.
中科院分区：
文献类型：
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作者：
Hertenberger, S.;Rudolph, D.;Koblmueller, G.
我们确定了整个生长参数空间和速率限制机制，在非催化InAs纳米线（NWs）生长的分子束外延。令人惊讶的巨大的生长温度范围被发现与最高温度接近类似600摄氏度的V/III比急剧增加后，远远超过了催化剂辅助的InAs纳米线的典型生长温度范围。基于定量原位视线四极质谱，我们确定在高温InAs纳米线生长的速率限制因素，通过直接监测的临界解吸和热分解过程的InAs纳米线。在动态（生长）和静态（无生长，超高真空）条件下，（111）取向的InAs纳米线在高温下表现出优异的热稳定性，即使在可忽略的过饱和度。因此，InAs NW生长的速率限制因素主要是由从衬底表面的脱附。III族和V族通量对生长速率的依赖性的更仔细的研究揭示了两种明显的生长制度，由有效As/In通量比定义的富As和富In制度，以及>6 μ m·h（-1）的最大可实现生长速率。高T生长和优异的热稳定性的独特功能提供了机会，在苛性环境下的InAs基NW材料的操作，并进一步允许访问的温度制度，适合于合金化非催化InAs NW与GaAs。
We identify the entire growth parameter space and rate-limiting mechanisms in non-catalytic InAs nanowires (NWs) grown by molecular beam epitaxy. Surprisingly huge growth temperature ranges are found with maximum temperatures close to similar to 600 degrees C upon dramatic increase of V/III ratio, exceeding by far the typical growth temperature range for catalyst-assisted InAs NWs. Based on quantitative in situ line-of-sight quadrupole mass spectrometry, we determine the rate-limiting factors in high-temperature InAs NW growth by directly monitoring the critical desorption and thermal decomposition processes of InAs NWs. Both under dynamic (growth) and static (no growth, ultra-high vacuum) conditions the (111)-oriented InAs NWs evidence excellent thermal stability at elevated temperatures even under negligible supersaturation. The rate-limiting factor for InAs NW growth is hence dominated by In desorption from the substrate surface. Closer investigation of the group-III and group-V flux dependences on growth rate reveals two apparent growth regimes, an As-rich and an In-rich regime defined by the effective As/In flux ratio, and maximum achievable growth rates of >6 mu m h(-1). The unique features of high-T growth and excellent thermal stability provide the opportunity for operation of InAs-based NW materials under caustic environment and further allow access to temperature regimes suitable for alloying non-catalytic InAs NWs with GaAs.