Characteristics of low-temperature-grown GaN films on Si(111) Z. Hassan a, * , Y.C. Lee a , F.K. Yam a , K. Ibrahim a , M.E. Kordesch b , W. Halverson c , P.C. Colter c a School of Physics, Universiti Sains Malaysia, Minden, Gelugor, Penang 11800, Malaysia b Department of Physics and Astronomy, Ohio University, Athens, OH, USA c Spire Corporation, Bedford, MA, USA Received 10 August 2004; received in revised form 26 October 2004; accepted 17 November 2004 by H. Takayama Available online 7 December 2004 Abstract In this paper, we report on the characteristics of GaN films grown on Si(111) at a low temperature (200 8C) by electron cyclotron resonance (ECR) plasma-assisted metalorganic chemical vapor deposition (PA-MOCVD). Structural analysis of the GaN films was performed by using scanning electron microscopy (SEM), atomic force miscroscopy (AFM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), and Rutherford backscattering spectrometry (RBS). Post deposition analysis revealed high quality crystalline GaN was obtained at this low temperature. Electrical analysis of the GaN films was done by using current–voltage (I–V) measurements where electrical characterizations were carried on GaN/Si heterojunction and Schottky barrier diodes. Rectification behaviour was observed for the isotype GaN/Si (n–n) heterojunction. Ideality factors and Schottky barrier heights for Ni and Cr Schottky barriers on GaN, were deduced to be 1.4 and 1.7; and 0.62 and 0.64 eV, respectively. q 2004 Elsevier Ltd. All rights reserved. PACS: 81.15.Gh; 61.10.Ki; 73.61.Ey Keywords: A. Semiconductors; B. Crystal growth; C. X-ray diffraction; D. Electrical properties. 1. Introduction The wide band gap semiconductors of the nitrides such as GaN, AlN and their alloys, have received enormous attention as ideal materials for optoelectronic and high- temperature/high-power devices due to their unique proper- ties, such as large direct band gap, high breakdown field and high thermal conductivity [1]. Although higher quality GaN films can be produced by growing GaN on substrates like sapphire (Al 2 O 3 ) or silicon carbide (SiC) but due to great interest in commercial growth for large size wafers at low cost, GaN films grown on Si(111) have become of great interest. In application purposes, GaN film grown on Si is expected to be an excellent candidate for the integration of GaN-based optoelectronic devices with Si-based electronic technology. Current research activities are mainly focused on epitaxial GaN films grown at high temperatures. However, recent studies [2,3] have shown that amorphous (a-GaN) and microcrystalline GaN (mc-GaN) may also have promise as novel electronic materials. The special attribute of these materials is the ability to deposit inexpensively over large area at low temperatures. The development of device quality films, grown at low temperatures, widens the range of possible substrates that can be used and thus will reduce the cost of technology. Thus, whereas epitaxial GaN films is the choice at present for short wavelength emitters and 0038-1098/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssc.2004.11.022 Solid State Communications 133 (2005) 283–287 www.elsevier.com/locate/ssc * Corresponding author. Tel.: C604 6533673; fax: C604 6579150. E-mail addresses: zai@usm.my (Z. Hassan), leeyc1979@yahoo.com (Y.C. Lee).