NOVELTY - The method comprises forming an array (100) of silicon nanowire structures, forming a patterned protective layer on the array of silicon nanowire structures, where the patterned protective layer defines a covered region and a uncovered region on the array of silicon nanowire structures, removing the array of silicon nanowire structures defined on the uncovered region using a selective etching, and removing the patterned protective layer remained on the array of silicon nanowire structures.    USE - The method is useful for fabricating a patterned silicon nanowire array (claimed), which is useful: for applying on surfaces of solar cells for enhancing absorption of sunlight or for solar panel applications; and for forming heterostructures such as carbon nanotubes used for a field emission display.    ADVANTAGE - The method enables economic, efficient and simple fabrication of the patterned silicon nanowire array with high uniformity and quality and larger area.    DETAILED DESCRIPTION - The method comprises forming an array (100) of silicon nanowire structures, forming a patterned protective layer on the array of silicon nanowire structures, where the patterned protective layer defines a covered region and a uncovered region on the array of silicon nanowire structures, removing the array of silicon nanowire structures defined on the uncovered region using a selective etching, and removing the patterned protective layer remained on the array of silicon nanowire structures. The step of forming the array of silicon nanowire structures comprises: forming a metal layer with a predetermined thickness on a silicon substrate by a coating process; performing a metal-induced chemical etching for the silicon substrate using an etching solution; and rinsing the metal layer from the silicon substrate. The step of forming the patterned protective layer comprises: oxidizing the array of silicon nanowire structures forming an oxide layer (110) on a surface of the array of silicon nanowire structures; patterning the oxide layer so that the array of silicon nanowire structures have the oxide layer on the covered region and expose silicon nanowires on the uncovered region; coating a photoresist layer over the array of silicon nanowire structures, where a space between the silicon nanowires is filled with the photoresist layer; and patterning the photoresist layer so that the array of silicon nanowire structures have the photoresist layer on the covered region and simultaneously expose the silicon nanowires (120) on the uncovered region. The step of oxidizing the array of silicon nanowire structures comprises immersing the array of silicon nanowire structures in a nitric acid solution. The step of patterning the oxide layer comprises a photolithography process. The step of selective etching comprises: immersing the array of silicon nanowire structures, which have the oxide layer, in 60 wt.% of a potassium hydroxide (KOH) solution at room temperature so as to etch the silicon nanowires exposed on the uncovered region of the array of silicon nanowire structures; or immersing the array of silicon nanowire structures, which have the photoresist layer, in an aqueous solution containing hydrofluoric acid and nitric acid so as to etch the silicon nanowires exposed on the uncovered region of the array of silicon nanowire structures. The step of patterning the photoresist layer comprises an exposure process and a development process. INDEPENDENT CLAIMS are included for:    (1) a method for fabricating heterojunctions on a patterned silicon nanowire array; and    (2) a method for fabricating a silicon microstructure.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic sectional view of an array of silicon nanowire structures.    Array of silicon nanowire structures (100)    Oxide layer (110)    Silicon nanowires (120)    Covered region (C)    Uncovered region. (U)