Light induced nickel plating method for p-type silicon and n/p solar cell material

Abstract

A simple and fast light induced nickel plating method for p-type silicon wafer and n/p silicon solar cell material is revealed. When a n/p solar cell or p-Si semiconductor substrate, which is subjected to metallization with metal contact on the rear side, is immersed in a plating bath, metal ions are reduced on the front surface of semiconductor as soon as illumination starts on the front. The mechanism of nickel plating in this invention is nickel electroplating under the reduction reaction with the use of interfacial potential between the nickel plating bath and the metal surface. It does not need any surface catalytic processing and extra voltage. Instead, it can carry out the nickel deposition on the specific surface with a high nickel plating rate, a simple process and a low production cost.

What is claimed is: 
     
         1 . A simple and fast light induced nickel plating method for p-type silicon wafer and n/p silicon solar cell material at least comprising the following steps:
 Step 1: taking a silicon substrate, and forming a layer of aluminum metallic film on a p-type surface thereof after cleaning so as to obtain a plated sample after sintering;   Step 2: formulating a nickel plating bath in a translucent container;   Step 3: cleaning the surface of the plated sample again, and removing a native oxide layer;   Step 4: immersing the plated sample in the nickel plating bath;   Step 5: emitting a light source directly on a plated surface of the plated sample for nickel deposition; and   Step 6: after the scheduled time for the nickel deposition, the light source is removed and the plated sample is taken out to wash and then to dry so that the light induced nickel plating on the plated sample is completed and a metallic film on silicon substrate is obtained.   
     
     
         2 . The method of  claim 1 , wherein the silicon substrate is of p-type silicon wafer and n/p silicon solar cell material. 
     
     
         3 . The method of  claim 1 , wherein the container at Step 2 is a translucent container. 
     
     
         4 . The method of  claim 1 , wherein the nickel plating bath at Step 2 bases on a mixed aqueous solution of nickel chloride and boric acid, and is placed at room temperature while stirring. 
     
     
         5 . The method of  claim 1 , wherein the light source at Step 5 is a lamp or sunlight. 
     
     
         6 . The method of  claim 1 , wherein the scheduled time for nickel deposition is one minute to two minutes.