Growth and Characterization of ZnO nano-rods on Si substrate by pulsed laser ablation
- PDF / 1,053,958 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 4 Downloads / 209 Views
M8.26.1
Growth and Characterization of ZnO nano-rods on Si substrate by pulsed laser ablation Vinay Gupta, P. Bhattacharya, Yu. I.Yuzyuk and R.S.Katiyar Department of Physics, PO Box 23343 Univ. of Puerto Rico, San Juan, PR
Abstract: Zinc oxide (ZnO) nanorods were fabricated directly on silicon substrate with diameters in the range of 70-350 nm and up to 15 µm long using pulsed-laser deposition at a relatively low processing temperature (450 oC) without any catalytic template. The influences of substrate temperatures and the oxygen pressures on the formation of ZnO nanorods were investigated. The Raman scattering studies and scanning electron microscopy results indicated that the ZnO nanorods were well aligned along c-axis and isolated from each other. The additional Raman modes at ~ 477 cm-1 and 574 cm-1 were observed in the c-axis oriented ZnO nanorods which attributed to the activation of the upper and lower surface phonon modes respectively.
Introduction: ZnO, a II-VI wide bandgap (3.3 eV) semiconductor with a large exciton binding energy (60 meV) has been considered a promising material for applications in modern nano-electronics and photonics1-8. Very recent demonstrations of novel ZnO devices include a nano-scale laser2 and the electrochemically gated quantum dot transistor3. ZnO nanoclusters and thin films have shown highly efficient exciton UV lasing action under the optical pumping4-6. The fabrication of large quantities of well-aligned ZnO nanorods in single crystalline form is extremely important for developing high efficiency shortwavelength optoelectronic nanodevices and gas sensors. Moreover, the synthesis of vertically aligned ZnO nanorods directly on silicon are necessary for the integration of the existing microelectronic technology with the nanoscale functional devices. In the last few years, several methods such as metal-organic vapor phase epitaxy (MOVPE) 7, metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE) 9, pulsed laser deposition (PLD) 10, thermal evaporation11, physical vapor deposition5, 6,8,12 etc., are reported for fabrication of ZnO nanorods. Well aligned c-axis oriented nanorods were grown either on the epitaxially matched substrates (e.g. Sapphire) and/or using the catalytic templates, and normally at high processing temperatures (700-1000 oC). The PLD has been given rare attention for the fabrication of ZnO nanorods. The PLD maintains the stoichiometry, and leads to the fabrication of epitaxial and single crystalline films at relatively lower temperatures. Furthermore, very little is known about the vibrational spectra of ZnO nanorods12. In this letter, we demonstrated fabrication of a large quantity of well aligned and c-axis oriented ZnO nanorods directly on Si utilizing pulsed laser deposition (PLD) technique at relatively low processing temperature (~500 ºC) without using any catalytic template.
M8.26.2
(004)
(110)
(100)
(102)
(100) (002) (101)
Intensity (arb. unit)
ZnO nanorods were fabricated by pulsed-laser deposition (KrF, 248 nm) using
Data Loading...
