Synthesis and characterization of silicon nanowires.
Date of Issue2009
School of Mechanical and Aerospace Engineering
Silicon nanowires have been proven to exhibit interesting properties different from their bulk counterparts. Due to the decrease in size, many applications can utilize silicon nanowires’ unique properties in the ever-shrinking electrical components today. This project focuses on the different electroless-etching methods of obtaining consistent silicon nanowires to be tested for its properties. A stainless steel autoclave was designed for this project to be used in an oven where temperature can be varied. This autoclave is used in the first method, where the silicon wafer is first electroplated with silver nitrate and hydrofluoric acid solution and then soaked in iron nitrate and hydrofluoric acid solution to be placed in the oven. The second method involves soaking the silicon wafer in the etching solution in an enclosed Teflon container for different lengths of time. The third method is a derivation of the second method but with the container being opened. Lastly, the fourth method is done by electroplating the silicon wafer in the etching solution for 10 minutes and then left in the solution for different periods of time. After running the various test methods, it has been found that method 4 produces the most consistent results and the dimensions of the nanowires obtained were compared with the etching times. It has been observed that when etch time is increased, the length of the nanowires will increase. Also, the diameter will decrease when etch time is longer. This project is optimally continued with investigation into the thermal properties of the silicon nanowires obtained. Due to the time constraints, future work should be done to verify thermoelectric and other properties of the silicon nanowires. Also, parameters could be further varied to find the influence of them on the morphology and properties.
Final Year Project (FYP)
Nanyang Technological University