Non-Polar Wurtzite (1120) GaN/AlN Quantum Dots for Highly Efficient Opto-Electronic Devices

Seoung-Hwan Park,Doyeol Ahn

doi:10.3390/electronics9081256

Seoung-Hwan Park, Doyeol Ahn

Open Access

https://doi.org/10.3390/electronics9081256

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Abstract

In III-nitride quantum dots (QDs), optical transition rate is very low because of the large built-in electrostatic field caused by the spontaneous polarization (SP) and piezoelectric (PZ) effects. In this work, we study the screening potential which is a solution of the self-consistent Hartree equation taking into account the built-in electrostatic field and its effect on light emission characteristics of non-polar wurtzite (WZ) (112¯0) GaN/AlN QD. It is found that the light emission intensity of the non-polar (112¯0) GaN/AlN QD structure is expected to be about four times larger than that of the c-plane (0001) GaN/AlN QD structure because the y-polarized matrix elements in the non-polar QD are larger than that in the c-plane QD. These predictions indicate that non-polar GaN/AlN QD structure have strong potential for highly efficient opto-electronic devices.

Highlights

Wurtzite (WZ) GaN-based quantum dots (QDs) have attracted significant attention as promising candidates for application in optical, optoelectronic, and electronic devices [1,2,3,4,5,6,7]
We expect that the internal field effect can be reduced for the non-polar GaN/AlN QD structure
GaN/AlN QD structure shows that the screening potential along z-axis is larger than that along x- or y-axis because there exists larger internal field along z-axis due to the spontaneous polarization

Summary

Introduction

Wurtzite (WZ) GaN-based quantum dots (QDs) have attracted significant attention as promising candidates for application in optical, optoelectronic, and electronic devices [1,2,3,4,5,6,7]. These structures have large spontaneous (SP) electric dipoles along the [0001] direction (c-axis) of the lattice on top of strong piezoelectric (PZ) polarization [8,9], which results in the substantial reduction of transition probability between the electrons and holes in heterostructures. The growth axes for c-plane and a-plane correspond to (0001)- and (112̄0)-orientations

Theory

Self-Consistent Calculation

Optical Matrix Element and Spontaneous Emission Coefficient

Results

Conclusions