Electronic band structure of polytypical nanowhiskers: a theoretical approach based on group theory and k$\cdot$p method

TL;DR

This paper develops a theoretical model using group theory and the k·p method to analyze the electronic band structure of polytypical nanowhiskers, focusing on the effects of phase alternation on their electronic and optical properties.

Contribution

It introduces a new model for polytypical nanowhiskers that combines group theory and k·p methods, applicable to single quantum wells, to predict electronic and optical behaviors.

Findings

Predicted spatial carrier separation in nanowhiskers.

Identified polarization effects in luminescence spectra.

Estimated range for spontaneous polarization in WZ InP.

Abstract

Semiconductor nanowhiskers made of III-V compounds exhibit great potential for technological applications. Controlling the growth conditions, such as temperature and diameter, it is possible to alternate between zinc blend and wurtzite crystalline phases, giving origin to the so called polytypism. This effect has great influence in the electronic and optical properties of the system, generating new forms of confinement to the carriers. A theoretical model capable to accurately describe electronic and optical properties in these polytypical nanostructures can be used to study and develop new kinds of nanodevices. In this study, we present the development of a wurtzite/zincblend polytypical model to calculate the electronic band structure of nanowhiskers based on group theory concepts and the k$\cdot$p method. Although the interest is in polytypical superlattices, the proposed model was applied to a single quantum well of InP to extract the physics of the wurtzite/zincblend polytypism. By the analysis of our results, some trends can be predicted: spatial carriers' separation, predominance of perpendicular polarization (xy plane) in the luminescence spectra and interband transition blueshifts with strain. A possible range of values for the WZ InP spontaneous polarization was suggested.