Scanning near-field optical microscopy (SNOM) analysis of MOVPE InN

Hiroshi Miwa ,  Yasuhiko Nagai ,  Akihiro Hashimoto ,  Akio Yamamoto 

University of Fukui (U. Fukui), 3-9-1 Bunkyo, Fukui 910-8507, Japan


Recently, we have attained a mobility of 1100 cm2/Vs and carrier concentration of 4.5×1018cm-3 for InN films grown by the atmosphere pressure MOVPE [1]. However, compared with MBE InN, MOVPE InN still has inferior electrical and optical properties. FWHM for PL peaks for MOVPE InN [2] is considerably larger than that for MBE InN [3], in spite of the similar PL peak energies. Therefore, MOVPE InN seems to have a large nonuniformity in their properties. In this paper, we report the scanning near-field optical microscopy (SNOM) analysis of MOVPE InN to get information about the nonuniformity. Samples of InN are grown at 600ºC on nitrided (0001) sapphire substrates without or with a GaN buffer by the atmospheric-pressure MOVPE. In the SNOM system (Type NFS-220FK, JASCO Corp., Japan.), a green laser (l= 532 nm) is used as an excitation source. A probe with an aperture size of 100-500 nmφ is used to illuminate the sample surface and collect near-field light (illumination-collection mode). A near-field PL spectrum and its intensity mapping are successfully obtained for InN films at room temperature for the first time. By monitoring a probe movement at each point of measurement, surface topography is also obtained. A large nonuniformity in the near-field PL mapping is observed for samples grown without buffer. Compared with films grown without buffer, those grown with a GaN buffer have a excellent uniformity in near-field PL intensity. Thus, the use of the buffer is found to improve effectively the in-plane uniformity of the near-field PL intensity. This seems to be due to the uniform nucleation of InN on the buffer. [1] A. Yamamoto et al., (will be presented in ICNS-6). [2] A. Yamamoto et al., J. Cryst. Growth 261 (2004) 275. [3] F. Chen et al., Physica E 20 (2004) 308.

Legal notice
  • Legal notice:

    Copyrighted materials, (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, stored in or introduced into a retrieval or caching system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), or for any purpose, 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: must be provided.


Related papers
  1. Recent Advances in InN-based Solar Cells; Status and Challenges in InGaN and InAlN Solar Cells
  2. Growth of N-polarity InN by ArF-laser assisted MOVPE
  3. Inhomogeneities in MOVPE InN
  4. A comparative study on MOVPE InN films grown on 3c-SiC/Si(111) and sapphire substrates

Presentation: poster at E-MRS Fall Meeting 2005, Symposium A, by Hiroshi Miwa
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-20 12:55
Revised:   2009-06-07 00:44
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine