Influence of polarization-induced electric field on the wavelength and the absorption coefficient of the intersubband transitions in AlxGa1-xN/GaN double quantum wells.

The influence of the polarization-induced electric field on the wavelength and the absorption coefficient of the intersubband transitions (ISBTs) in Al_xGa_1-xN/GaN coupled double quantum wells (DQWs) have been investigated by self-consistent calculation. It is found that the wavelength of the ISBT between the first odd order and the second even order subbands (the 1_odd-2_even ISBT) can be shortened to 1.3 μm owing to the Stark shift induced by the polarization effect. The absorption coefficient of the 1_odd-2_even ISBT decreases by increasing the polarization field discontinuity. On the other hand, a shorter wavelength and a larger absorption coefficient of the ISBTs are obtained by decreasing the width of the central barrier of Al_xGa_1-xN/GaN DQWs. The results are beneficial to achieving devices operation within the optical communication wavelength range. [ABSTRACT FROM AUTHOR]