Stain-etched silicon powder
The present invention is for a porous silicon powder comprising silicon particles wherein the outermost layers of said particles are porous. The present invention is also directed to a method of making this porous silicon powder using a stain etch method. The present invention is also directed to a method of making silicon nanoparticles from the porous silicon powders using a process of ultrasonic agitation. The present invention also includes methods of processing these silicon nanoparticles for use in a variety of applications.
1. A porous silicon powder comprising a plurality of silicon particles wherein only the outermost layers of said particles are porous, and wherein the outermost porous layers of said silicon particles comprise a thickness which ranges from at least about 1 angstrom to at most about 500 nanometers.
2. The porous silicon powder of claim 1 , wherein the silicon particles have an average particle diameter which ranges from at least about 10 nanometers to at most about 1 millimeter.
3. The porous silicon powder of claim 1 , wherein the outermost porous layers of said silicon particles comprise a porosity which ranges from at least about 5 percent to at most about 95 percent.
4. The porous silicon powder of claim 1 , wherein the outermost porous layers of said silicon particles comprise pores having sizes which range from at least about 1 nanometer to at most about 100 nanometers.
5. The porous silicon powder of claim 1 , wherein said powder has a purity which ranges from at least about 80 percent to at most about 100 percent.
6. The porous silicon powder of claim 1 , further comprising a dopant species dispersed in the silicon particles, wherein the silicon particles serve as a matrix for the dopant species.
7. The porous silicon powder of claim 6 , wherein the dopant species renders the porous silicon powder n-doped.
8. The porous silicon powder of claim 6 , wherein the dopant species renders the porous silicon powder p-doped.