Imaging Transport Disorder in Conducting Arrays of Metallic Quantum Dots: An Experimental and Computational Study

✍ Scribed by J.L. Sample; K.C. Beverly; P.R. Chaudhari; F. Remacle; J.R. Heath; R.D. Levine

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 324 KB
• Volume: 14
• Category: Article
• ISSN: 0935-9648
• DOI: 10.1002/1521-4095(20020116)14:2<124::aid-adma124>3.0.co;2-n

✦ Synopsis

growth method be applied to the growth of nanowires made of other materials? These questions are the subject for further studies in our group.

In conclusion, we discovered a new method for synthesizing long and highly ordered amorphous silicon oxide nanowires in bulk quantities. The length of the nanowires can reach a few millimeters. These aligned nanowires have a great potential for use as intense blue light emitters. [5,8,9] More work is underway to better understand the growth mechanism and to prepare nanowires with different diameters and/or different materials.

Experimental

SiO x nanowires were prepared in a typical CVD setup equipped with a oneinch tube furnace and gas flow controller. P-type Si(111) wafers were ultrasonically cleaned in acetone for 5 min, then etched in 10 % HF for 5 min, and finally rinsed in deionized water. A drop (0.3 g) of molten gallium (99.999 %) was placed on a Si wafer, which was then transferred into the center of a 1-inchdiameter quartz tube inside the tube furnace. Another small alumina boat with 1±3 mL deionized water was then placed inside the tube at the carrier gas entry point. The system was degassed under vacuum and purged with hydrogen at 200 sccm for 10 min before the starting materials were heated. The reaction temperature was ~920±940 C and the reaction time was 1±3 h. During the reaction, the hydrogen flow rate was constant at 30 sccm. After the furnace was slowly cooled down to room temperature, one or several pearl-like white balls were found on the Si wafer.

The as-grown SiO x nanowires were analyzed by SEM (HITACHI S-3200N) at 5 kV. The microstructure characterization was carried out using TEM (Philips 301) at 80 kV. The HRTEM image was taken in a Philips CM-200 microscope operated at 200 kV. The chemical compositions were determined by an XPS instrument (Riber MIQ 236) and by an EDX spectrometer attached to the SEM instrument.