Light-emitting semiconductor device using group III nitride compound

A Group III nitride compound semiconductor comprising:

• a triple layer structure having an emission layer sandwiched between an n-type cladding layer and a p-type cladding layer;
• said emission layer satisfying the formula Alx1Gay1In1-x1-y1N, where 0≦x1≦1, 0≦y1≦1, and 0≦x1+y1≦1, and having a thickness larger then diffusion length of holes;
• said n-type cladding layer satisfying the formula Alx2Gay2In1-x2-y2N, where 0≦x2≦1, 0≦y2≦1and 0≦x2+y2≦1, being doped with a donor impurity, and having a lattice constant substantially equal to a lattice constant of said emission layer:
• and
• said p-type cladding layer satisfying the formula Alx3Gay3In1-x3-y3N, where 0≦x3≦1, 0≦y3≦1, and 0≦x3+y3≦1, being doped with an acceptor impurity, having a forbidden band sufficiently wider than a forbidden band of said emission layer to confine electrons injected into said emission layer.