Removal of Surface States and Recovery of Band-Edge Emission in InAs Nanowires through Surface Passivation
Removal of Surface States and Recovery of Band-Edge Emission in InAs Nanowires through Surface Passivation
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DOI：
10.1021/nl300015w
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发表时间：
2012-07-01
期刊：
影响因子：
10.8
通讯作者：
Ning, C. Z.
中科院分区：
文献类型：
--
作者：
Sun, M. H.;Joyce, H. J.;Ning, C. Z.
由于半导体纳米线的表面体积比大，表面缺陷态在表面附近聚集，因此表面态对纳米线的光学和电子性能及其基于光发射的应用是有害的。在本文中，我们展示了一种有效的方法来消除锌-闪锌矿（ZB）和纤锌矿（WZ）结构的InAs NWs的表面状态，并通过有机硫化物十八烷基硫醇（ODT）表面钝化来显着恢复带边发射。在钝化前后进行了微光致发光（PL）测量，研究了NWs的主要重组机制和表面态密度。对于WZ-NWs，我们发现钝化去除了表面状态并恢复了带边发射，导致PL线宽减少了19倍。对于ZB-NWs，深表面态被去除，PL峰宽度变窄至250 nm左右，保留了一些近带边表面态的发射。钝化后的NWs在大气、水和热环境中均表现出良好的稳定性。特别是，钝化后的NWs在空气中暴露超过5个月后，其PL特征没有发生明显变化。
Surface states in semiconductor nanowires (NWs) are detrimental to the NW optical and electronic properties and to their light emission-based applications, due to the large surface-to-volume ratio of NWs and the congregation of defects states near surfaces. In this paper, we demonstrated an effective approach to eliminate surface states in InAs NWs of zinc-blende (ZB) and wurtzite (WZ) structures and a dramatic recovery of band edge emission through surface passivation with organic sulfide octadecylthiol (ODT). Microphotoluminescence (PL) measurements were carried out before and after passivation to study the dominant recombination mechanisms and surface state densities of the NWs. For WZ-NWs, we show that the passivation removed the surface states and recovered the band-edge emission, leading to a factor of similar to 19 reduction of PL linewidth. For ZB-NWs, the deep surface states were removed and the PL peaks width became as narrow as similar to 250 nm with some remaining emission of near band-edge surface states. The passivated NWs showed excellent stability in atmosphere, water, and heat environments. In particular, no observable changes occurred in the PL features from the passivated NWs exposed in air for more than five months.