Some effects of conduction band nonparabolicity on electron reflection spectrum of multiquantum barriers

The effect of nonparabolicity of conduction band on the electron reflection spectrum of multiquantum barriers (MQB) has been examined. Drastic reducti on in the effective barrier height is expected by adopting the nonparabolic model on the MQB which had been designed using the parabolic model for 1.5 mu m semiconductor lasers (LDs). The predicted enhancement in barrier heig ht by the MQB is over 600 meV under parabolic model. However, it decreases to 40 meV under nonparabolic model with the same structure. On the other ha nd, the experimental enhancement in barrier height by the MQB is estimated to be around 30 meV on 1.5 mu m LDs, close to the value calculated by nonpa rabolic model. Those results suggest that a much higher effective barrier h eight can be realized by optimizing the MQB design taking the nonparabolici ty into account. The conduction band nonparabolicity was incorporated by th e k.p perturbation method, (C) 1998 American Institute of Physics. [S0021-8 979(98)03021-7].