硫化鋅鎘三元奈米線之合成、鑑定與能隙可調變性之研究

Synthesis, Characterization and Band Gap Engineering of Ternary ZnxCd1-xS (0≦x≦1) Alloyed Nanowires

蘇柏睿(Po-Jui Su)

指導教授 ： 陳力俊

國立清華大學/工學院/材料科學工程學系/碩士(2014年)

摘要

近年來，許多研究團隊都致力於三元合金半導體奈米線之研究，藉由調變三元合金之能隙以改變半導體之結構與光性質，使三元合金半導體比二元半導體蘊藏著更多變的、更特殊的特徵；光電性質的可調變性使得三元合金半導體奈米線被廣泛的運用在可變波長式奈米雷射、光檢測器、發光二極體及光伏元件上。硫化鎘與硫化鋅皆為相當重要且被廣為使用在光電元件上的二六族半導體材料，將硫化鎘及硫化鋅混合形成三元合金更可使其使用光譜範圍擴大。
在此研究中，利用單一步驟之氣-液-固相成長反應，成長出硫化鋅鎘三元半導體奈米線，藉由控制沉積區的溫度，可以在單一試片上生長出各種不同合金成分之硫化鋅鎘奈米線，從X-ray 繞射分析儀中可以得到所有的奈米線沒有相分離且皆為纖鋅礦結構，在光致發光量測中可以得到硫化鋅鎘奈米線的能隙可從富硫化鎘的綠光端 (508 nm) 調變至富硫化鋅的紫外光端 (360 nm)，此代表藉由控制奈米線的沉積溫度，我們可以自由控制硫化鋅鎘三元合金的成分、結構以及能隙。

關鍵字

三元奈米線 ； 能隙調變 ； 光學性質調變 ； 硫化鋅鎘

並列摘要

A complete composition tunability of ternary ZnxCd1-xS alloyed nanowires on a single substrate has been achieved by vapor–liquid–solid (VLS) growth. The compositions of the as-grown nanowires along the substrate can be modulated from pure ZnS to pure CdS by simply controlling the local temperature. Photoluminescence spectra showed that the band edge emissions of these alloyed nanowires with the peak wavelength can be gradually tuned from green (508 nm) at the CdS-rich end to near UV (360 nm) at the ZnS-rich end.
Alloyed semiconductor nanowires have drawn much interest in recent years because they can offer more unique properties than binary systems by band-gap engineering. Band gap is one of the most important parameters of semiconductor materials and determines its electronic and optical properties. Ternary alloyed nanowires offer a wide range of band gap tunability, provide broad applications in optoelectronics, including wavelength-tunable lasers, multispectral photodetectors, light emitting diodes (LEDs) and photovoltaics (PV).
CdS and ZnS with band gaps of 2.42 eV and 3.7 eV at 300 K, respectively, are the promising II-VI semiconductor materials due to their wide range of optoelectronic application. Alloyed ZnxCd1-xS nanowires are expected to provide band gap tunability. Recently, there have been a few reports on the synthesis of ternary ZnxCd1-xS alloyed nanowires by solvothermal synthesis or laser ablation deposition. However, it is still a challenge to achieve a complete composition variation of ZnxCd1-xS nanowires on a single substrate in a one-step synthesis. Herein, we report a route for the preparation of ternary ZnxCd1-xS alloyed nanowires via a one-step vapor-liquid-solid (VLS) growth. Crystalline nanowires with full-range composition tuning were achieved by controlling the substrate temperature. Band gap tuning of these nanowires allows emissions from green (508 nm) to near UV (360 nm) region.

並列關鍵字

ternary alloyed nanowires ； band gap engineering ； optical tunability ； zinc cadmium sulfide

參考文獻

62. Y. C. Cheng, C. Q. Jin, F. Gao, X. L. Wu, W. Zhong, S. H. Li and P. K. Chu, “Raman Scattering Study of Zinc Blende and Wurtzite ZnS,” Journal of Applied Physics 106, pp. 123505 (2009).

31. Z. P. Liu, D. Xu, J. B. Liang, J. M. Shen, S. Y. Zhang, and Y. T. Qian, “Growth of Cu2S Ultrathin Nanowires in a Binary Surfactant Solvent,” Journal of Physical Chemistry B 109, pp. 10699-10704 (2005).

2. R. P. Feynman, “There’s Plenty of Room at the Bottom,” at the Annual Meeting of the American Physical Society on December 29th at the California Institute of Technology (1959).

3. A. P. Alivisatos, “Semiconductor Clusters, Nanocrystals, and Quantum Dots,” Science 271, pp. 933-937 (1996).

4. S. E. Thompson and S. Parthasarathy, “Moore's Law: the Future of Si