High efficiency group iii-v compound semiconductor solar cell with oxidized window layer

Abstract

The present application utilizes an oxidation process to fabricating a Group III-V compound semiconductor solar cell device. By the oxidation process, a window layer disposed on a cell unit is oxidized to enhance the efficiency of the solar cell device. The oxidized window has an increased band gap to minimize the surface recombination of electrons and holes. The oxidized window also improves transparency at the wavelengths that were absorbed in the conventional window layer.

1 . A solar cell device, comprising:
 at least one cell unit formed from a Group III-V compound semiconductor material, the cell unit being configured to absorb predetermined wavelengths of a solar spectrum; and   an oxidized window layer disposed on the cell unit to prevent recombination of photo-generated carriers at a top surface of the solar cell device.   
     
     
         2 . The solar cell device of  claim 1 , wherein a band gap of the oxidized window layer is about 4.0 eV. 
     
     
         3 . The solar cell device of  claim 1 , wherein the oxidized window layer comprises an Al-containing Group III-V compound semiconductor material. 
     
     
         4 . The solar cell device of  claim 1 , wherein the window layer comprises an InAlP material or an AlGaAs material. 
     
     
         5 . The solar cell device of  claim 1 , wherein the cell unit is formed from any of Gallium Arsenide (GaAs), Gallium Indium Phosphide (Ga 1-x In x P), Gallium Indium Arsenide (Ga 1-x In x As), Indium Phosphide (InP) and Gallium Indium Arsenide Phosphide (Ga 1-x In x As 1-y P y ), and Aluminum Gallium Indium Phosphide ((Al x Ga 1-x ) 1-y In y P). 
     
     
         6 . The solar cell device of  claim 1 , wherein the device comprises a plurality of cell units, each cell unit being configured to absorb different wavelengths of the solar spectrum. 
     
     
         7 . The solar cell device of  claim 1 , further comprising:
 a substrate on which the cell unit is formed, wherein the substrate is formed of at least one of Gallium Arsenide (GaAs), Indium Phosphide (InP) or Germanium (Ge).   
     
     
         8 . The solar cell device of  claim 1 , further comprising:
 a cap layer disposed on the window layer to enhance an electrical contact with a metal conductive material disposed on the cap layer.   
     
     
         9 . The solar cell device of  claim 1 , further comprising
 a backside contact disposed on a bottom surface of the substrate.   
     
     
         10 . The solar cell device of  claim 1 , wherein the window layer is oxidized by a wet oxidation process.