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 AlxGa1−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 1odd-2even ISBT) can be shortened to 1.3μm owing to the Stark shift induced by the polarization effect. The absorption coefficient of the 1odd-2even 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 AlxGa1−xN∕GaN DQWs. The results are beneficial to achieving devices operation within the optical communication wavelength range.