Method of preparing green-emitting gallium phosphide diodes by epitaxial solution growth

Abstract

Abstract GREEN-EMITTING ELECTROLUMINESCENT GALLIUM PHOSPHIDE DIODES ARE GROWN BY LIQUID PHASE EPITAXY. A GA-GAP MELT CONTAINED IN A COVERED CRUICIBLE IS PLACED IN A VERTICAL FURNACE. A GAP SUBSTRATE WAFER IS INSERTED INTO THE MELT WHICH HAS BEEN MAINTAINED AT A TEMPERATURE OF ABOUT 1110-1140*C. AN N-TYPE GAP LAYER IS PRODUCED BY THE ADDITION OF A DOPANT SELECTED FROM S, SE, AND TE TO THE MELT WHICH IS SLOWLY COOLED TO A TEMPERATURE OF ABOUT 1070-1100*C., AT WHICH TIME THE MELT IS COUNTERDOPED WITH AN ACCEPTOR DOPANT, E.G., ZN OR CD. THE MELT IS FURTHER COOLED TO ABOUT 1030-1060*C., CAUSING THE GROWTH OF A P-TYPE LAYER, AFTER WHICH THE SUBSTRATE IS REMOVED FROM THE METAL AND FURTHER COOLED TO AMBIENT TEMPERATURES. ELECTROLUMINESCENT DIODES ARE THEN PREPARED BY THINNING THE SUBSTRATE SIDE OF THE WAFER TO REDUCE SERIES RESISTANCE. AU-ZN AND AU-SN ALLOY DOTS ARE APPLIED TO THE P AND N SIDE RESPECTIVELY, OF SAWED OR CLEAVED SECTIONS OF THE WAFER. GREEN-EMITTING DIODES PREPARED BY THE ABOVE METHOD HAVE EFFICIENCIES OF ABOUT 2.7X10-4, WHICH EFFICIENCIES CAN BE IMPROVED BY A FACTOR OF 2 OR MORE BY COATING THE DIODES WITH ANTI-REFLECTIVE EPOXY COATINGS. THE DIODES FIND UTILITY AS PANEL INDICATORS.

Inventors

• 👤 Samuel E Blum
• 👤 Luther M Foster
• 👤 Kwang K Shih
• 👤 Jerry M Woodall

Bibliographic Details