Screening influence on the Stark effect of impurity states in strained wurtzite GaN/Al_xGa_(1-x)N he

• 作 者: 张敏 班士良
• 机 构: Department of Physics,School of Physical Science and Technology,Inner Mongolia University,College of
• 出 处: Chinese Physics B
• 发表日期: 2009年12期
• 关键词: impurity Stark screening strained hydrostatic areal coherent shallow weakening d

The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/Al x Ga 1 x N heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation.The variations of Stark energy shift with electric field,impurity position,Al component and areal electron density are discussed.Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states.For a given impurity position,the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect.The weakening of the blue and red shifts,induced by the screening effect,strengthens gradually with the increase of electric field.Furthermore,the screening effect weakens the mixture crystal effect,thereby influencing the Stark effect.The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.

The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN / Al x Ga 1 x N heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. variations of Stark energy shift with electric field, impurity position, Al component and areal electron density are discussed. Our results show that the that the preparation for reducing both reduces the blue and red shifts as well as the binding energies of the states. For given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. weakening the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field .Furthermore, the screening effect weakens the mixture crystal effect, thereby influencin g the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.