Effect of built-in electric field and impurity on binding energy of cylindrical quantum dot with two electrons

Abstract

Abstract:

Based on the framework of effective-mass approximation and variational approach, The influence of built-in electric field and an impurity on the binding energy of a cylindrical wurtzite GaN/AlxGa1-xN quantum dot(QD) with two electrons is discussed. The numerical results show that while the charge of impurity is negative, the impurity state would be instable. When there is a donor impurity with positive charge e in the center of QD , the binding energy of impurity to electron firstly increases rapidly, reachs a maximum value, then decreases with increasing the height and radius of QD. With increasing Al content, the binding energy increases monotonically. The binding energy of impurity to electron firstly increases, and then decreases with moving the impurity position from the bottom of QD to the top, there is a maximum. In comparison with the single-electron impurity states, the influence of the built-in electric field on the binding energy of two-electron quantum dot system is more obvious. While the QD height L is smaller than 6nm in the WZ GaN/Al0.15Ga0.85N QD with the radius R=5nm, the binding energy of two-electron quantum dot system with impurity would be larger than that of the single-electron impurity states. while the QD height L is larger than 6nm, the binding energy of two-electron quantum dot system with impurity would be smaller than that of the single-electron impurity states.

Key words: optoelectronics, cylindrical quantum dot, built-in electric field, impurity, two-electron, binding energy

CLC Number:

O472

ZHENG Dong-mei, WANG Zong-chi, SU Chun-yan. Effect of built-in electric field and impurity on binding energy of cylindrical quantum dot with two electrons[J]. J4, 2011, 28(1): 96-103.

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