| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress coupling between a second sub band of a quantum well layer and an outer bulk layer in an optical control type nonlinear optical semiconductor element in a near IR region using a intersubband transition, and to realize both of strong intersubband absorption and fast absorption recovery time. SOLUTION: In the nonlinear optical semiconductor device using a nonlinear optical response based on the saturation of the intersubband absorption of a semiconductor multiple quantum well structure, the multiple quantum well structure 4 is disposed between a GaN base layer 3 and a GaN cap layer 5 and is formed by laminating an AlGaN barrier layer 6 and a GaN well layer 7. The quantum well structure has subband energy modulation regions 8, 9 in the interfaces with the adjacent layers 3, 5 in such a manner that the energy of the second subband in each quantum well layer once decreases and then again increases toward the adjacent layer.</p> |
