Method of manufacturing semiconductor nanowires

#1. Field of the Invention

#The present invention relates generally to the manufacture of semiconductor nanowires and, more specifically, to the manufacture of silicon nanowires on conducting substrates, and to selected applications and end uses of the resulting structures.

#2. Description of the Prior Art

#FIG. 1 is a view of a graphite cloth starting substrate at enlargement of X20.

#FIG. 2 is a view of the same graphite cloth with nanowires grown on the substrate at enlargement of X1,000.

#FIG. 3 is an enhanced view of the graphite cloth with nanowires at enlargement of X2,000.

#The present invention provides a relatively simple and uncomplicated method for producing semiconductor nanowires, and more specifically, silicon nanowires. For a frame of reference, the term “nanowire”, as used in the discussion which follows, generally refers to any elongated conductive or semiconductive material that includes at least one cross sectional dimension that is less than 500 nm and has an aspect ratio (length:width) of greater than 10, possibly even greater than 100. For example, in the preferred embodiment of the present invention, nanowires are grown which are on the order of 100-250 nm in width and tens of micrometers in length.

#In the method of the invention, a high surface area growth of semiconductor nanowires is obtained on a conducting substrate. A selected graphite material, preferably a commercially available graphite cloth, is provided as the conducting substrate. The semiconductor nanowire is grown on the substrate and then detached from the substrate. The commercially available graphite cloth can be obtained from a number of sources. For example, POCO Graphite of Decatur, Tex., sells a 5 micron particle size sheet material with a uniform microstructure that resists wear and has good thermal conductivity for dimensional stability. Example dimensions are on the order of 0.100×4″×6 for the on-the-shelf product.

#In an example laboratory run, a thin gold film twenty nanometers thick is deposited via RF sputtering onto a ˜0.7 cm×1.0 cm piece of commercially-available graphite fabric (mass ˜10 mg). The graphite cloth has a number of properties which make it an ideal starting substrate for purposes of the present method. For example, the graphite is a good conductor of electricity. The material also has strong adhesion properties due to its high porosity and microroughness. In the next step in the method, the modified graphite cloth is then exposed to dilute silane (0.5% SiH4 diluted in He) with a flow rate of 40 sccm at 600° C. for 20 minutes, resulting in a uniform coating of Si nanowires; the average dimension of the nanowires is approximately 175 nanometers in width and tens of micrometers in terms of length.