Buried stressors in nitride semiconductors: Influence on electronic properties

Abstract

An analysis is presented on the effect of the strain field originating from a subsurface stressor ͑point source of dilatation or a dilatating ellipsoidal inclusion͒ on the electronic properties of nitride semiconductors. With good accuracy, real quantum dots can be modeled as such stressors. We consider the following material structure design: a uniform semi-infinite GaN matrix with a buried stressor or a GaN matrix with a single ͑In,Ga͒N quantum well, which is grown pseuodomorphically between the stressor and the free surface. We utilize isotropic elasticity to determine the strain field in the structures under investigation. We then apply a k·p perturbation theory approach to examine the shifts of the conduction and valence band edges caused by the stressor. We find lateral confinement for electrons and holes, which can be proposed for the realization of strain-induced quantum dots in the quantum well.

Elastic and piezoelectric fields due to polyhedral inclusions

“…Although numerical simulations provide a complete solution to the problem, analytical calculations still play an important role. In a number of studies it has been confirmed that descriptions of quantum dots using idealized analytical models and more rigorous numerical techniques are in good agreement (Daruka et al, 1999;Andreev et al, 1999;Romanov et al, 2001Romanov et al, , 2005Jonsdottir et al, 2006). Exact analytical formulas can significantly facilitate analysis of material properties.…”

Elastic Field of a Dilatational Cylindrical Inclusion in an Elastically Isotropic Half-Space

“…The obtained results demonstrate that when an inclusion is placed in an elastic half-space, hydrostatic stress occurs and depends on the relative position between the cylinder and the free surface. This affects the mechanical and physical properties of the material, which has been proven by many studies [8].…”

“…The correctness of the found elastic fields of cylinder in the elastic half-space given by Eqs. (8)(9)(10)(11)(12)(13) is checked by comparing to the case of infinite space, where the hydrostatic stress on the outside of the cylinder is zero [13]. There is hydrostatic stress in the elastic half-space Eqs (14), similar to the elastic field of ITDD in the half-space [10].…”

“…From Eqs. (8)(9)(10)(11)(12)(13) it follows that the elastic field in the medium depends on the position of the cylinder relative to the free surface and the size of the cylinder. The results also show that, when approaching the free surface, the influence of the free surface on the elastic field of DCI increases.…”

“…The stressors, e.g., inclusions, which are located in an elastic medium, act as the source of the elastic field inside the solid, and thus affect the physical and mechanical properties of the material. First, the stored elastic energy associated with stressors can be released giving rise to the formation of various defects [6][7][8][9], such as dislocations, cracks, etc. Second, stressors induce elastic distortions changing interatomic distances from their equilibrium values and thus changing material properties [10,11].…”