To determine lattice polarity is an important issue in InN research since it leads to various differences in growth behaviours and properties such as crystal growth modes, surface stability, and impurity incorporation. In this presentation, a novel way was proposed to determine lattice polarity by using circular photogalvanic effect (CPGE).

In CPGE, a net current was generated without adding any external bias under the irradiation of a circular polarized light. This CPGE current was observed in as-grown InN layers in a magnitude of several nA, Origin of the CPGE can be attributed to lack of spatial inversion symmetry. The former degeneration band splits into two bands with opposite spin indices as symmetry reduced. When the InN layer is radiated by circular polarized light, an asymmetry distribution of excited electrons in momentum space is generated due to optical selection rules, which leads to a net current in the InN.

As a wurtzite semiconductor, InN is lacking of inversion symmetry. Along c-direction, the lattice of In-polarity can be regarded as a complete inversion of that of N-polarity. Thus the spin-orbit interaction in InN with contrary polarities should be opposite, resulting in opposite spin splitting. Therefore, the sign of photocurrent due to CPGE should be opposite for InN layers with different polarities because of the opposite spin splitting. This prediction was then confirmed by the experimental observation that both CPGE photocurrents and their dependences on the incident phase angle are opposite for InN layers with different polarities. Furthermore, it was found that the above phenomenon is independent of conduction type, i.e. both n- and p-type InN shows the same sign of CPGE current and the same dependence on the incident phase angle as well. Therefore, polarity of InN can be easily determined by investigating their CPGE photocurrents.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/18362 must be provided.

1. Recent advances and challenges in p-type doping of InN and InN-based novel nanostructures
2. Effects of threading dislocations and other defects on reduction of band-edge photoluminescence in n-InN films
3. Epitaxy Control and Characterization of InN, InN-based Ternary Alloys, and Their MQW-structures