EPITAXIAL WAFER AND LED MANUFACTURED USING THE WAFER

摘要

PROBLEM TO BE SOLVED: To increase the light output of a LED by allowing the carrier density of a graded composition layer in an epitaxial layer to have such a carrier density profile that may have the maximum value at a place within the graded composition layer a specified distance away from the termination point within the graded composition layer. SOLUTION: This epitaxial wafer has an n-type GaAsP epitaxial layer 16 on an n-type single crystalline substrate 20. The epitaxial layer 16 at least comprises a graded composition layer 21 and fixed composition layers 22 and 23. The carrier density of the graded composition layer 21 has such a carrier density profile that may have the maximum value at a place within the graded composition layer (including the termination point) 2 μm or more away from the termination point within the graded composition layer. The start point and the termination point of an epitaxial layer such as the graded composition layer mean a start point and a finish point of growth of the layer respectively. For example, the maximum value of the n-type carrier density is 2-30×1017 cm-3.