Graded-Gap and Quantum-Well Injection a-SiC:H p-i-n Light-Emitting Diodes

As alternative approaches to improve the performance of hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLED’s), graded p-i junction and quantum-well-injection (QWI) structures have been incorporated into the i-layer of p-i-n TFLED’s. The electroluminescence (EL) intensity of TFLED’s with graded p-i junction is 100 times higher than that of basic p-i-n TFLED’s and about 35 times lower than that of conventional green LED’s at the same injection current density. The EL intensity of QWI TFLED’s is also 20 times higher than that of basic p-i-n TFLED’s. For graded-gap TFLED’s, a red-orange light emission was experimentally observed by naked eyes, while for QWI TFLED’s a yellow-like one was observed.