Interband optical transitions due to ionized acceptor bound excitons in wurtzite GaN strained cylindrical quantum dot

Abstract

Abstract:

Considering the strong built-in electric field(BEF) in the wurtzite cylindrical GaN quantum dot(QD) with finite potential barriers, the interband optical transitions due to the exciton bound by an ion with charge ?e (called ionized acceptor bound exciton (A?, X) ) are investigated theoretically by means of a variational method. Numerical results show that the emission wavelengths sensitively depend on the QD size(L and R), the position of the ionized acceptor and the Al composition x of the barrier material AlxGa1-xN. The transition wavelength is increased if the QD height, the QD radius and Al composition x are increased. The emission wavelength firstly increases when the ionized accptor is moved from the left barrier of the QD to right along z-direction, and reaches its maximum when the acceptor is in the vicinity of the left interface of the QD. Then the transition wavelength decreases if the acceptor is continuously moved toward right. The minimum value of the transition wavelength can be obtained when the acceptor is in the vicinity of the right interface of the QD. The wavelength is increased again if the acceptor is further moved to the right barrier of the QD. The emission wavelength increases when the acceptor position goes from the center of the QD. Comparing with the free exciton state without the acceptor, the emission wavelength increases with introducing the ionized accptor impurity into the left side of the QD center, and the emission wavelength reduces with introducing the ionized accptor impurity into the right side of the QD center.

Key words: optoelectronics, cylindrical quantum dot, built-in electric field, ionized acceptor bound exciton, emission wavelength

CLC Number:

O472+3

ZHENG Dong-mei, WANG Zong-chi. Interband optical transitions due to ionized acceptor bound excitons in wurtzite GaN strained cylindrical quantum dot[J]. J4, 2012, 29(4): 385-391.

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