Effect of Nonparabolicity on Linear and Nonlinear Optical properties in AlxGa1-xN/GaN Single Quantum Well Under External Applied Field.

In this work, the effect of positive and negative dc field on the linear and nonlinear optical absorption coefficients and changes in refractive indices under nonparabolicity effect in AlxGa1-xN/GaN single quantum well (QW) has been investigated theoretically. The internal electric field in the QW is evaluated using the spontaneous and piezoelectric polarization. Using Airy function method, the effective mass equation including the conduction band nonparabolicity, is used to obtain energy eigen values and their corresponding envelope functions. It is found that the conduction band nonparabolicity has a significant effect on energy levels as well as on optical properties and the optical properties get blue-shifted. It is obvious because the dipole matrix elements and intersubband energy increases with increasing applied field. The band nonparabolicity gives a remarkable effect under negative bias incomparable with positive bias