Title :
The use of Ga in two-step processing to optimize the electronic properties of CuInxGa1-xSe2 solar cells
Author :
Zafar, S. ; Sankaranarayanan, H. ; Jayapalan, A. ; Narayanaswamy, R. ; Ferekides, C.S. ; Morel, D.L.
Author_Institution :
Dept. of Electr. Eng., Univ. of South Florida, Tampa, FL, USA
fDate :
29 Sep-3 Oct 1997
Abstract :
We have developed techniques for effectively incorporating Ga in CIGS within the confines of our manufacturing-friendly process. Near Cu/(In+Ga)=1 collection lengths of 1-2 μm can be attained resulting in consistent Jsc´s of 40 mA/cm2. As the metal ratio is decreased below 1, there is an unusual abrupt increase in Eg of 50 mV and a significant deterioration of electronic properties. These properties are discussed in terms of interplay between process control of kinetics and thermodynamics and the dictates of the phase diagram. A key objective which we have attained is the ability to independently optimize surface and bulk properties. Using these techniques we have raised our Voc´s above 500 mV for devices with band gaps of 0.95 eV and have achieved 13% device efficiency
Keywords :
copper compounds; energy gap; gallium compounds; indium compounds; solar cells; ternary semiconductors; thermodynamic properties; 0.95 eV; 13 percent; 500 mV; CuInxGa1-xSe2 solar cells; CuInGaSe2; band gaps; bulk properties; collection lengths; electronic properties optimisation; kinetics; phase diagram; process control; surface properties; thermodynamics; two-step processing; Annealing; Kinetic theory; Manufacturing processes; Photonic band gap; Photovoltaic cells; Process control; Semiconductor films; Space charge; Thermodynamics; Zinc oxide;
Conference_Titel :
Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3767-0
DOI :
10.1109/PVSC.1997.654107
