Abstract: Under the effectives-mass envelope-function theory, the binding energy of the system in symmetric double quantum wells are theoretically calculated using the variational method. The influence of applied external electric fields, barrier height, quantum well width and the position of donors on the binding energies of donor impurities are investigated. The quantum well potential energy changes significantly with applied external electric filed. The binding energy and the wave functions with the donor in the different position are presented without and with external electric field. Variations of donor binding energy with the centre barrier width are also calculated. With the fixed the middle barrier of double quantum wells, the binding energy increases until it reaches a maximum value, and then decreases as the well width increases. The results are meaningful and can be applied in the design of optoelectronic devices based on quantum well structures.

Key words: optoelectronics, binding energy, neutral donor, variational method, shooting method, symmetric double quantum well