| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide the band structure of a light emitting layer in which recombination of electron and hole contributive to light emission takes place more frequently. <P>SOLUTION: In the band drawing of 2. A in Fig. 2, a composition unstable region 901 formed in the vicinity of interface of n-layer 98 in a light emitting layer 90 has a conduction band at a part lower than the central part 900 and electrons tends to pile up. Similarly, a composition unstable region 902 has a valence band at a part higher than the central part 900 and holes tends to pile up. Under that state, electrons injected from the n-layer 98 (left side on the drawing) piles up in the composition unstable region 901, and holes injected from the p-layer 99 (right side on the drawing) piles up in the composition unstable region 902. When recombination of electron and hole contributive to light emission takes place only in the central part 900 of the light emitting layer 90, emission efficiency lowers. On the contrary, when the light emitting layer 90 does not have the composition unstable region 901 and the composition unstable region 902, as shown at 2. B on Fig. 2, emission efficiency can be enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
