Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Effect of growth temperature on the morphology and phonon properties of InAs nanowires on Si substrates | Li et al. Nanoscale Research Letters 2011 6 463 http content 6 1 463 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Effect of growth temperature on the morphology and phonon properties of InAs nanowires on Si substrates 13 1 2 1 1 1 1 1 Tianfeng Li Yonghai Chen Wen Lei Xiaolong Zhou Shuai Luo Yongzheng Hu Lijun Wang Tao Yang and Zhanguo Wang1 Abstract Catalyst-free vertical array of InAs nanowires NWs are grown on Si 111 substrate using MOCVD technique. The as-grown InAs NWs show a zinc-blende crystal structure along a 111 direction. It is found that both the density and length of InAs NWs decrease with increasing growth temperatures while the diameter increases with increasing growth temperature suggesting that the catalyst-free growth of InAs NWs is governed by the nucleation kinetics. The longitudinal optical and transverse optical TO mode of InAs NWs present a phonon frequency slightly lower than those of InAs bulk materials which are speculated to be caused by the defects in the NWs. A surface optical mode is also observed for the InAs NWs which shifts to lower wave-numbers when the diameter of NWs is decreased in agreement with the theory prediction. The carrier concentration is extracted to be X 1017 cm-3 from the Raman line shape analysis. A splitting of TO modes is also observed. PACS Introduction Semiconductor nanowires NWs have been intensively studied in the last decade due to their novel physical properties and potential applications in high-performance devices such as field-effect transistors lasers photodetectors and photovoltaic devices 1-5 . Such NWs are usually grown through vapor-liquid-solid mode where metal nanoparticles Au Ni or other metals act as catalysts 6-9 . However for certain materials the metal c atalysts can result in unintentional incorporation into pure crystalline NWs which causes serious problems for materials doping and limits their .
