＜正＞ With the use of variational method to solve the effective mass equation, we have studied the electronicand sballow impurity states in semiconductor heterostructures under an applied electric field. The electron energy levelsare calculated exactly and the impurity binding energies are calculated with the variational approach. It is found thatthe behaviors of electronic and shallow impurity states in heterostructures undee an applied electric field are analogousto that of quantum wells. Our results show that with the increasing strength of electric field, the electron confinementenergies increase, and the impurity binding energy increases also when the impurity is on the surface, while the impuritybinding energy increases at first, to a peak value, then decreases to a value which is related to the impurity positionwhen the impurity is away from the surface. In the absence of electric field, the result tends to the Levine’s ground stateenergy （-1/4 effective Rydberg） when the impurity is on the surface, and the ground impurity binding energy tends tothat in the bulk when the impurity is far away from the surface. The dependence of the impurity binding energy on theimpurity position for different electric field is also discussed.
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