Quantitative measurements of internal electric fields with differential phase contrast microscopy on InGaN/GaN quantum well structures. Issue 1 (8th October 2015)

• Record Type: Journal Article
• Authors: Lohr, Matthias; Schregle, Ralph; Jetter, Michael; Wächter, Clemens; Müller‐Caspary, Knut; Mehrtens, Thorsten; Rosenauer, Andreas; Pietzonka, Ines; Strassburg, Martin; Zweck, Josef
• Is Part Of: Physica status solidi. Volume 253:Issue 1(2016)
• Page Start: 140
• Page End: 144
• Publication Date: 2015-10-08
• Subjects: DPC -- Efficiency droop -- EFTEM -- electric fields -- GaN -- HAADF -- IMFP -- MQW -- QCSE -- quantification -- STEM; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201552288
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract: Piezoelectric and spontaneous polarization play an essential role in GaN‐based devices. InGaN quantum wells (QWs) in GaN host material, especially grown along the polar c ‐direction, exhibit strong internal fields in the QW region due to the indium‐induced strain. An exact knowledge of the electric fields is essential, since they are one of the factors limiting the performance of green LDs and LEDs. Differential phase contrast in a scanning transmission electron microscope enables direct, local, and quantitative measurements of these electric fields. For a multi‐QW sample, it was possible to determine the piezoelectric field in the range of 43–67 MV m −1 with a resolution of 10 MV m −1 ( ≡ 10 mV nm −1 ).