Abstract: The energy levels are calculated by using finite different method with Matlab language in two ＂W＂ type wells, which one is parabolic （WI type） and the other is triangle （WII type） in wells. The results have shown that when the middle-potential barrier （ Vb） is fixed, the value of each level increases with increasing edge-potential barrier （Vo） , the split begins with the higher level, then the lower levels. In comparison with WI type, a previous split for the higher levels in WII type can be seen as V0 is increased. The opposite case appears for an in- creasing value of Vb and a given value of V0 as well as for simultaneously increasing values of Vb and Vo. The smallest two levels in WI type are stable as the value of Vo/Vb varies. The level value in WII type is larger than the corresponding level in WI type under the same potential barriers. This shows that there is a stronger coupling in WI type in comparison with WII type. The results may provide some theoretical references for the band design of double quantum wells.

Key words: ＂W＂ type well, energy levels, comparative study