Stoichiometric Effect on Electrical, Optical, and Structural Properties of Composition-Tunable InxGa1鈥?i>xAs Nanowires
详细信息 查看全文
- 作者：Jared J. Hou ; Fengyun Wang ; Ning Han ; Fei Xiu ; SenPo Yip ; Ming Fang ; Hao Lin ; Tak F. Hung ; Johnny C. Ho
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：October 23, 2012
- 年：2012
- 卷：6
- 期：10
- 页码：9320-9325
- 全文大小：418K
- 年卷期：v.6,no.10(October 23, 2012)
- ISSN：1936-086X
文摘
Ternary InGaAs nanowires have recently attracted extensive attention due to their superior electron mobility as well as the ability to tune the band gap for technological applications ranging from high-performance electronics to high-efficiency photovoltaics. However, due to the difficulties in synthesis, there are still considerable challenges to assess the correlation among electrical, optical, and structural properties of this material system across the entire range of compositions. Here, utilizing a simple two-step growth method, we demonstrate the successful synthesis of composition and band gap tunable InxGa1鈥?i>xAs alloy nanowires (average diameter = 25鈥?0 nm) by manipulating the source powder mixture ratio and growth parameters. The lattice constants of each NW composition have been well correlated with the chemical stoichiometry and confirmed by high-resolution transmission electron microscopy and X-ray diffraction. Importantly, the as-grown NWs exhibit well-controlled surface morphology and low defect concentration without any phase segregation in all stoichiometric compositions. Moreover, it is found that the electrical nanowire device performances such as the turn-off and ION/IOFF ratios are improved when the In concentration decreases at a cost of mobility degradation. More generally, this work suggests that a careful stoichiometric design is required for achieving optimal nanowire device performances.