Time dependent phenomena associated to charge transport along double barrie
r heterostructures are studied. Systems in 3D under the effect of an extern
al magnetic field along the current and 1D systems are analyzed. Together w
ith static multistabilities in the negative resistance region of the I-V ch
aracteristic curve, we found self-sustained time dependent current and char
ge oscillations. The nature of this oscillatory behavior depends upon the p
arameters that define the system.