IN-SITU HYDROGENATION OF VISIBLE A-SIC-H-BASED P-I-N TYPE THIN-FILM LIGHT-EMITTING-DIODES USING THE PHOTOCHEMICAL VAPOR-DEPOSITION METHOD

The effects of in situ hydrogenation on the performance of visible a-S iC:H-based p-i-n type thin-film light-emitting diodes (TFLEDs) have be en investigated. The TFLEDs were fabricated with a photochemical vapou r deposition method. In the process of TFLED fabrication, with a strea m of H-2 of 50 sccm and ultraviolet light irradiation at a substrate t emperature of 250 degrees C and a process pressure of 0.3 Torr for 30 min, in situ hydrogenation was performed at the base of a p layer with various thicknesses of i-a-SiC:H layers (0, 10, 20 and 30 nm). It was found that the performance of visible TFLEDs was dramatically improve d by in situ hydrogenation. With in situ hydrogenation after depositio n of the 30 nm thick luminescently active i-a-SiC:H layer, the thresho ld voltage was decreased by about 2 V, the electroluminescence peak sh ifted from 680 nm to 625 nm and the brightness increased from 1.3 cd m (-2) to 80 cd m(-2).