The effect of temperature on the creation of gallium oxide nanowires
The materials required for this science fair project:
- 6 gallium beads, each measuring 1mm in diameter
- 1 aluminum tube furnace
- 1 cylinder of argon gas
- 6 pieces of silicon wafer
- Ni(NO3)2 solution (nickel nitrate solution)
- 1 beaker of water
- 1 ceramic plate
- 1 vacuum pump
- 1 electron microscope
1. For this experiment, the independent variable is the temperature used for synthesizing the gallium nanowires. The dependent variable is the formation of the gallium nanowires on the substrate, which will be determined through observing the silicon wafers under an electron microscope. The constants (control variables) are the size of the wafers, the thickness of the Ni(NO3)2 substrate, the size of the gallium beads, the rate of increase in temperature and the level of pressure in the tube.
2. Coat a silicon waferwith Ni(NO3)2 solution and heat it to allow the water to evaporate. Repeat the process 2 more times. A thin coating of the substrate will then form on the surface of the silicon wafer. The film of substrate will act as the catalyst for the synthesis of gallium oxide nanowires.
3. Place the silicon wafer on a ceramic plate, with the gallium bead at the side. Place the plate inside the tube of the aluminum tube furnace. Then, position the beaker filled with water on the upstream end of the tube.
4. Fix the other end of the tube to a vacuum pump and remove all the air within. Fill the tube with argon gas.
5. While maintaining the argon gas flow at 90sccm and the pressure at 300 torr, increase the temperature of the furnace at a rate of 17 °C per minute. When the temperature of the furnace has reached 860 °C, maintain the new temperature for 20 minutes before reducing it to its original temperature, at the rate of 17 °C per minute.
6. Allow the silicon wafer to cool downand observed under an electron microscope to see if any gallium oxide nanowires have been successfully synthesized. Record the results , as shown below.
7. Repeat steps 2 to 6 at the higher temperatures of 880 °C, 900 °C, 920 °C, 940 °C and 960 °C. Record all results in a table, as shown below.
Proper supervision by a qualified laboratory technician is required.