Patent Number: 
Section: claims

1. A method of producing compound nanorods without employing external catalyst, comprising:using an ultrafast pulsed laser to ablate portions of a solid target comprising a compound material;depositing a first portion of ablated target material onto a substrate to form a seed layer, wherein the first portion deposited onto the substrate comprises nanoparticles, and wherein a fluence provided with at least one ultrafast pulse that ablates target material is substantially lower than a plasma threshold of the target material;annealing the substrate to improve the crystallinity of the seed layer; anddepositing a second portion of ablated target materials onto the seeded substrate to form nanorods, wherein the second portion deposited onto the substrate comprises vapor, and wherein a fluence provided with at least one ultrafast pulse that ablates target material is greater than a plasma threshold of the target material. 2. The method of claim 1, where neutral gases are fed into the deposition chamber to be radicalized by the laser ablation plume and participate in the growth. 3. The method of claim 1, wherein for depositing the seed layer, a laser fluence is chosen to be below a predetermined threshold fluence. 4. The method of claim 3, wherein the said predetermined threshold fluence is the plasma formation threshold Fth for the target material. 5. The method of claim 3, wherein the said predetermined plasma formation threshold Fth of said target material is determined by plotting the ion current collected by an ion probe as a function of the laser fluence, and determining the fluence at which the plot exhibits a distinct change in the slope, below which the ion current becomes vanishing. 6. The method of claim 1, wherein for depositing the seed layer, the laser fluence is chosen to be below 4×Fth. 7. The method of claim 1, wherein for depositing the nanorods after the seed layer preparation, the laser fluence is chosen to be above the plasma formation threshold Fth of the target material. 8. The method of claim 1, wherein the pulsed laser generates at least one pulse having a pulse duration between 10 fs and 100 ps. 9. The method of claim 1, wherein the pulsed laser generates at least one pulse having a pulse energy between 1 microJ and 100 milliJ. 10. The method of claim 1, wherein the pulsed laser generates pulses at a repetition rate between 1 Hz and 100 MHz. 11. The method of claim 1, wherein the target compound material comprises a metal oxide. 12. The method of claim 1, wherein the target compound material comprises a nitride. 13. The method of claim 1, wherein the target material comprises a metal and the growth occurs through reaction with a reactive gas. 14. The method of claim 1, wherein the said ablation and deposition are performed in an environment having a reactive background gas, the reactive gas selected from a group of reactive gases comprising at least one of oxygen, nitrogen, NH3, NO, NO2, or N2O, supplied either in neutral or in plasma form. 15. The method of claim 1, wherein the target compound material comprises arsenide. 16. The method of claim 1, wherein the substrate temperature for the seed layer and nanorod growth is between room temperature and 1000° C. 17. The method of claim 1, wherein a composite of nanorods of different materials are deposited using different target materials. 18. The method of claim 1, wherein the substrate temperature is above 500° C. 19. The method of claim 16, wherein the substrate temperature for the seed layer and nanorod growth is between 300° C. and 600° C. 20. The method of claim 1, wherein the laser fluence applied to the target material for depositing the first portion is less than the laser fluence applied to the target material for depositing the second portion. 21. A method of producing compound nanorods without employing external catalyst, the method comprising:ablating a target material with laser pulses, the laser pulses comprising at least one pulse having a pulse duration in the range from about 10 fs to 100 ps and providing a fluence substantially lower than a plasma threshold of the target material, the fluence sufficiently low such that at least a large portion of ablated material comprises nanoparticles;forming a seed layer on a substrate by depositing at least a portion of the nanoparticles on a substrate;ablating a target material with laser pulses, at least one pulse having a pulse duration in the range from about 10 fs to 100 ps and providing a sufficiently high fluence such that the ablated material comprises substantially vaporized target material; andforming nanorods on the seed layer by depositing at least a portion of the vaporized target material on the seeded layer. 22. The method of claim 21, wherein the sufficiently low fluence is near or below an ablation threshold of the target material. 23. The method of claim 21, wherein the sufficiently low fluence is characterizable by at least one of a weak ion signal and low plume brightness. 24. The method of claim 21, wherein the sufficiently high fluence is greater than an evaporation threshold of the target material.