Title :
Improved Conversion Efficiency of GaN/InGaN Thin-Film Solar Cells
Author :
Horng, Ray-Hua ; Lin, Shih-Ting ; Tsai, Yu-Li ; Chu, Mu-Tao ; Liao, Wen-Yih ; Wu, Ming-Hsien ; Lin, Ray-Ming ; Lu, Yuan-Chieh
Author_Institution :
Inst. of Precision Eng., Nat. Chung Hsing Univ., Taichung
fDate :
7/1/2009 12:00:00 AM
Abstract :
In this letter, we report on the fabrication and photovoltaic characteristics of p-i-n GaN/InGaN thin-film solar cells. The thin-film solar cells were fabricated by removing sapphire using a laser lift-off technique and, then, transferring the remaining p-i-n structure onto a Ti/Ag mirror-coated Si substrate via wafer bonding. The mirror structure is helpful to enhance light absorption for a solar cell with a thin absorption layer. After the thin-film process for a conventional sapphire-based p-i-n solar cell, the device exhibits an enhancement factor of 57.6% in current density and an increment in conversion efficiency from 0.55% to 0.80%. The physical origin for the photocurrent enhancement in the thin-film solar cell is related to multireflection of light by the mirror structure.
Keywords :
III-V semiconductors; current density; gallium compounds; indium compounds; laser materials processing; photoconductivity; semiconductor thin films; solar cells; thin film devices; wafer bonding; GaN-InGaN; conversion efficiency; current density; enhancement factor; laser lift-off technique; light absorption; light multireflection; mirror-coated substrate; p-i-n structure; photocurrent enhancement; photovoltaic characteristics; thin absorption layer; thin-film solar cells; wafer bonding; Laser lift-off; thin-film solar cell; wafer bonding;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2009.2021414