| 摘要 |
PURPOSE:To facilitate the manufacture and obtain high luminous efficiency, by forming an LED so as to be constituted of an N type Ca1-xAlx As layer and a P type Ga 1-xAlxAs and so that the value of x is in the specific range. CONSTITUTION:An LED is constituted by forming a P-N junction 13 constituted of a P type Ga 1-xAlxAs layer 11 and an N type Ga 1-xAlxAs layer 12. In this case, it is formed so that the value x of the Al mixed crystal is in the range of 0.05-0.4 on the surface of the layer 12 and 0.05 or less at the interface of the junction 13. In this constitution, the energy gap of the layer 12 expands together with the value x. Therefore, since the barrier of injected electrons at the P-N junction is almost neglected, the injection efficiency can be approximatively set at 1 resulting in the increase of the luminous efficiency. The absorption coefficient in a luminous wavelength decreases in the layer 12, and accordingly the luminous efficiency increases. Further, since the layers 12 and 11 can be formed by one time of liquid growing process, the defect of crystal in the neighborhood of the junction 13 reduces, and therefore the luminous efficiency can be enhanced. |
