Millimeter- and submillimeter-wave nanoscience : LDRD project 122359 final report.

Lee, Mark

Sandia National Laboratories

关键词: Spectra;    Nanowires.;    Phonons;    Optical Modes;    Phonons-Optical Properties.;   

DOI  :  10.2172/942189
RP-ID  :  SAND2008-5940
RP-ID  :  AC04-94AL85000
RP-ID  :  942189

美国|英语

来源: UNT Digital Library

【 摘 要 】

LDRD Project 122359 was a nine-month, late-start effort that pursued initial experiments studying the fundamental electrodynamic response properties of various nanomaterials from millimeter-wave (above roughly 30 GHz) up to submillimeter-wave (above roughly 0.1 THz) frequencies. The nine months of this project's duration produced two main empirical findings. First, Fourier transform reflectance spectroscopy on SrTiO{sub 3} nanocrystals from 0.2 to 10 THz frequency showed signatures of two optical phonons that correspond to known optical modes in bulk crystal SrTiO{sub 3}. However, quantitative differences between the nanoparticle and bulk spectra suggest that one or both of these phonons may shift frequency and weaken in nanoparticles relative to bulk crystal. Second, heavily doped n-type GaAs nanowires were synthesized for the purpose of creating high frequency diodes to study non-linear frequency conversion properties of compound semiconductor nanowires. It was found that incorporation of a heavy concentration of dopants interferes with the growth of these nanowires. While DC measurements showed reasonable diode-like current-voltage properties, the current state-of-the-art material properties of these nanowires are still unsuitable for millimeter-wave testing and applications.