Solar cell and texturing method thereof

Abstract

The present invention relates to a solar cell. The solar cell includes a substrate of a first conductive type, the substrate having a textured surface on which a plurality of projected portions are formed, and surfaces of the projected portions having at least one of a plurality of particles attached thereto and a plurality of depressions formed thereon; an emitter layer of a second conductive type opposite the first conductive type, the emitter layer being positioned in the substrate so that the emitter layer has the textured surface; an anti-reflection layer positioned on the emitter layer which has the textured surface and including at least one layer; a plurality of first electrodes electrically connected to the emitter layer; and at least one second electrode electrically connected to the substrate.

What is claimed is: 
     
         1 . A solar cell, comprising:
 a substrate of a first conductive type, the substrate having a textured surface on which a plurality of projected portions are formed, and surfaces of the projected portions having at least one of a plurality of particles attached thereto and a plurality of depressions formed thereon;   an emitter layer of a second conductive type opposite the first conductive type, the emitter layer being positioned in the substrate so that the emitter layer has the textured surface;   an anti-reflection layer positioned on the emitter layer which has the textured surface and including at least one layer;   a plurality of first electrodes electrically connected to the emitter layer; and   at least one second electrode electrically connected to the substrate.   
     
     
         2 . The solar cell of  claim 1 , wherein the plurality of particles are made of the same material as the substrate. 
     
     
         3 . The solar cell of  claim 1 , wherein the plurality of particles are made of silicon. 
     
     
         4 . The solar cell of  claim 1 , wherein each of the plurality of particles has a diameter of about 50 nm to 300 nm. 
     
     
         5 . The solar cell of  claim 1 , wherein the anti-reflection layer comprises a first anti-reflection layer positioned on the emitter layer which has the textured surface and a second anti-reflection layer positioned on the first anti-reflection layer. 
     
     
         6 . The solar cell of  claim 1 , wherein a size of each of the plurality of projected portions is about 20 to 40 times larger than a size of each of the plurality of depressions. 
     
     
         7 . The solar cell of  claim 1 , wherein each of the plurality of projected portions has a diameter of about 1 μm to 20 μm. 
     
     
         8 . The solar cell of  claim 1 , wherein each of the plurality of depressions has a depth of about 400 nm to 500 nm. 
     
     
         9 . The solar cell of  claim 1 , wherein diameters of the plurality of depressions are irregular.