Title :
Wide bandgap Cu(Ga,In)Se2/(Zn,Cd)S heterojunctions
Author :
Klenk, R. ; Mauch, R.H. ; Menner, R. ; Schock, H.W.
Author_Institution :
Inst. of Phys. Electron., Stuttgart Univ., West Germany
Abstract :
The preparation of thin-film heterojunctions for solar cells consisting of vacuum evaporated Cu(Ga,In)Se2 absorber and (Zn,Cd)S window layers is discussed. Efficiencies between 7.8% at 30% Ga and 6.7% at 70% Ga are reported. The open-circuit voltage increases according to the bandgap. Reasonable properties are obtained even for large deviations from stoichiometry to the Ga,In-rich side of the phase diagram in comparison to CuInSe2. Cells with high Ga content deteriorate during air annealing and improve with reducing treatments. Measurements of capacitance, jV-characteristic, and quantum efficiency indicate that the space-charge region is shifted into the window by annealing in air. Since the electrical field in the absorber decreases, fewer photogenerated carriers are collected.
Keywords :
II-VI semiconductors; cadmium compounds; copper compounds; energy gap; gallium compounds; indium compounds; p-n heterojunctions; semiconductor growth; semiconductor thin films; ternary semiconductors; vacuum deposited coatings; zinc compounds; 6.7 to 7.8 percent; CuGa1-xInxSe2-Zn1-xCdxS; absorber; air annealing; bandgap; capacitance; electrical field; heterojunctions; open-circuit voltage; quantum efficiency; semiconductor; solar cells; space-charge region; vacuum evaporated; window layers; Annealing; Capacitance measurement; Heterojunctions; Lighting; Photonic band gap; Photovoltaic cells; Propellants; Quantum capacitance; Sputtering; Substrates; Thin film circuits; Transistors; Voltage; Zinc;
Conference_Titel :
Photovoltaic Specialists Conference, 1988., Conference Record of the Twentieth IEEE
Conference_Location :
Las Vegas, NV, USA
DOI :
10.1109/PVSC.1988.105948
