Study of light efficiency and lifetime of LED with different surface structures

The main problem of GaAs based AlGaInP series LED is the low light extraction efficiency and heat generation inside, which have serious impact on the LED' lifetime. In this paper, we introduce a kind of LED with new surface structure formed of surface texture and light anti-reflecting layers through the post-epitaxial processing. In this new structure, the inside light transmission route has been changed and the current spreading is enhanced, which makes much more light emit outside. With the same injected current, the new LED' output light intensity is in average 15 times as the normal LED with the same epitaxial structure, and the ratio is larger than 15 as the injected current increases. The new LED's saturation current is as high as 125 mA because of the heat is decreased inside, the accelerated aging test shows that the new LED' lifetime is as long as 13×104 h for packaged ones and 19×104 h for unpackaged ones, which is suitable for working at large injected current especially.