Title :
The effect of Mo back contact on Na out-diffusion and device performance of Mo/Cu(In,Ga)Se2/CdS/ZnO solar cells
Author :
Al-Thani, Hamda A. ; Hasoon, Falah S. ; Young, Man ; Asher, Sally ; Alleman, Jeff L. ; Al-Jassim, Mowafak M. ; Williamson, Don L.
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
Molybdenum thin films were deposited on soda lime glass (SLG) substrates using direct-current planar magnetron sputtering, with a sputtering power density of 1.2 W/cm2. The working gas (Ar) pressure was varied from 0.6 to 16 mtorr to induce changes in the Mo films´ morphology and microstructure. Thin films of Cu(In,Ga)Se2 (CIGS) were deposited on the Mo-coated glass using the 3-stage co-evaporation process. The morphology of both the Mo-coated SLG and the CIGS thin films grown on it was examined using high-resolution scanning electron microscopy. Na was depth profiled in the Mo and CIGS films by secondary ion mass spectrometry. The device performance was evaluated under standard conditions of 1000 W/m2 and 25°C. Optimum device performance is found for an intermediate Mo sputtering pressure.
Keywords :
II-VI semiconductors; cadmium compounds; copper compounds; doping profiles; gallium compounds; indium compounds; metallic thin films; molybdenum; scanning electron microscopy; secondary ion mass spectra; semiconductor device measurement; solar cells; sputtered coatings; ternary semiconductors; zinc compounds; 0.6 to 16 mtorr; 25 degC; 3-stage co-evaporation process; CIGS; Mo back contact; Mo-Cu(InGa)Se2-CdS-ZnO; Mo/Cu(In,Ga)Se2/CdS/ZnO solar cells; Na out-diffusion; depth profiles; device performance; direct-current planar magnetron sputtering; film morphology; high-resolution scanning electron microscopy; microstructure; secondary ion mass spectrometry; Glass; Microstructure; Morphology; Photovoltaic cells; Photovoltaic systems; Solar power generation; Sputtering; Substrates; Thin film devices; Transistors;
Conference_Titel :
Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE
Print_ISBN :
0-7803-7471-1
DOI :
10.1109/PVSC.2002.1190666
