SEMICONDUCTOR LIGHT EMITTING ELEMENT

PURPOSE:To form a current constriction area out of a semiconductor layer of relatively small thickness by providing the element with such composition gradient that the forbidden band width on the clad layer side and the forbidden band width on the cap layer side charge continuously, and providing it with a mixed crystal semiconductor layer of the same conductivity type as the clad layer. CONSTITUTION:At the hetero junction interface between a semiconductor layer 10 having forbidden band width Ea and a semiconductor layer 11 having forbidden band width Eb (but Ea Eb), a semiconductor layer 12, wherein the forbidden band width changes continuously from Ea to Eb, is provided. The semiconductor layer 12 is provided in the stripe shape of extending vertically on the paper face. The semiconductor layer 12 has the same forbidden band widths as the semiconductor layers 10 and 11 at respective interfaces with the semiconductor layers 10 and 11, and is the grated layer wherein the forbidden band width changes continuously between these interfaces. Such grated layer has mixed composition of, for example, the semiconductor layer 10 and the semiconductor 11, and is of the same composition as the semiconductor layer 10 on the semiconductor layer 10 side, and can be formed by giving composition gradient so that it may be of the same composition as the semiconductor layer 11 on the semiconductor 11 side.