Tandem solar cell

Abstract

This application is related to a method of manufacturing a solar cell device comprising providing a substrate comprising Ge or GaAs; forming a first tunnel junction on the substrate, wherein the first tunnel junction comprises a first n-type layer comprising InGaP:Te, and a first alloy layer comprising AlxGa(1-x)As and having a lattice constant; adding a material into the first alloy layer to change the lattice constant; and forming a first p-n junction on the first tunnel junction.

What is claimed is: 
     
         1 . A method of manufacturing a solar cell device, comprising:
 providing a substrate comprising Ge or GaAs;   forming a first tunnel junction on the substrate, wherein the first tunnel junction comprises a first n-type layer comprising InGaP:Te, and a first alloy layer comprising Al x Ga (1−x) As and having a lattice constant;   adding a material into the first alloy layer to change the lattice constant; and   forming a first p-n junction on the first tunnel junction.   
     
     
         2 . The method of  claim 1 , wherein the first alloy layer has a p-type impurity. 
     
     
         3 . The method of claim I, wherein the first n-type layer or the first p-n junction comprises an element selected from the group consisting of Gallium, Aluminum, Indium, Arsenic, and Phosphorous. 
     
     
         4 . The method of  claim 1 , further comprising a step of forming a second tunnel junction on the first p-n junction, wherein the second tunnel junction comprises a first element with an atomic number larger than that of Gallium. 
     
     
         5 . The method of  claim 4 , wherein the first element has a concentration of 1˜2%. 
     
     
         6 . The method of  claim 4 , wherein the second tunnel junction comprises a second alloy layer and a second n-type layer between the second alloy layer and the substrate. 
     
     
         7 . The method of  claim 4 , further comprising:
 forming a third tunnel junction on the second tunnel junction, wherein the third tunnel junction comprises a third alloy layer having a second element with an atomic number larger than that of Gallium; and   forming a second p-n junction on the third tunnel junction.   
     
     
         8 . The method of  claim 7 , wherein the second element has a concentration between 3.5×10 21  and 1.7×10 22 (l/cm 3 ). 
     
     
         9 . The method of  claim 1 , further comprising a step of forming a buffer layer between the first tunnel junction and the substrate. 
     
     
         10 . The method of  claim 9 , wherein the buffer layer, the first tunnel junction, or the first p-n junction comprises an element selected from the group consisted of Gallium, Aluminum, Indium, Arsenic, and Phosphorous. 
     
     
         11 . The method of  claim 1 , wherein the material added into the first alloy has a concentration between 1˜2%. 
     
     
         12 . The method of  claim 1 , wherein the material is selected from the group consisting of Gallium, Aluminum, indium, Arsenic, and Phosphorous.