SEARCH

SEARCH BY CITATION

Keywords:

  • GaN, LED, electron holography

Abstract

Electron holography was used to measure the electrostatic potential distribution in an LED chip at high spatial resolution, from which the internal polarization field can be derived. A cross-sectional TEM lamella on a workable LED die containing five InGaN/GaN quantum wells (QWs) connected to electrodes that fit into an in-situ biasing TEM holder was prepared using a focused ion beam (FIB). Off-axis electron holography under Lorentz mode was carried out to study the p -MQW-n region and phase profiles were derived at different reverse biasing conditions. p -n contrast has been shown in the calibrated electrostatic potential mapping. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)