Anticrossing Gap between Pairs of the Subbands in Al_xGa_1-xN/GaN Double Quantum Wells

Dependences of anticrossing gaps between pairs of subbands in Al_xGa_1-xN/GaN double quantum wells (DQWs) on the width and the Al composition of the central barrier of the DQWs and on the well width of the DQWs have been investigated by solving the Schrödinger and Poisson equations self-consistently. It is found that the anticrossing gaps are not influenced by the polarization-induced electric field in the DQWs. The anticrossing gaps decrease with increasing the width and the Al composition of the central barrier of the DQWs, as well as with the increasing well width of the DQWs. According to the results of the calculation, the anticrossing gaps can reach 150meV in Al_xGa_1-xN/GaN DQWs. There is significant coupling between the two wells of the DQWs when the width of the central barrier of the DQWs is narrower than 2nm.