A variational method is adopted to investigate the ground state binding energy of an electron bound to a donor impurity near the interface of a single semiconductor heterojunction by considering the modification of the dielectric constant within a continuous dielectric theory. 采用连续电介质理论计入对材料介电常数的修正,利用变分法讨论半导体单异质结中界面附近的单电子束缚于施主杂质的基态结合能。