SEMICONDUCTOR LIGHT EMITTING DEVICE

PURPOSE:To improve the quantum efficiency of a semiconductor light emitting device of the structure having a lateral P-N junction in an active layer by forming a clad layer of a semi-insulating semiconductor layer, thereby decreasing a threshold current due to complete narrowing of the current. CONSTITUTION:A semi-insulating Al0.3Ga0.7As clad layer 12, an N type Al0.1 Ga0.9As active layer 13 and a semi-insulating Al0.3Ga0.7 clad layer 14 are sequentially laminated and grown on a GaAs substrate 11. When metal organic chemical vapor phase growing method is applied to the epitaxial growth of the layers 12, 14, preferable insulation can be obtained without intentionally containing an impurity. When voltages of the polarity having positive to a P side electrode 18 and negative to an N side electrode 19 are applied, a current is narrowed by the part of semi-insulating property of the layers 12, 14 to concentrate at the part of N type of the layer 13, and a laser oscillation is produced at the layer 13 of a P type region 17 between the N type layer and the P type region 16. In this case, since the current is completely narrowed, the threshold current decreases and the quantum efficiency is improved.