Journal of Crystal Growth 266 (2004) 455–460 Inﬂuence of threading dislocations on the properties of InGaN-based multiple quantum wells H.B. Yu*, H. Chen, Dongsheng Li, J. Wang, Z.G. Xing, X.H. Zheng, Q. Huang, J.M. Zhou State Key Laboratory for Surface Physics, Institute of physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, People’s Republic of China Received 18 January 2004; accepted 27 February 2004 Communicated by M. Schieber Abstract Therelationshipofthethreadingdislocations(TDs)andInGaN-basedquantumwell(QW)opticalcharacteristicsis studiedbytemperature-dependentphotoluminescence,high-resolutionX-raydiffractionandatomicforcemicroscopic. It is found that TDs deteriorate the QW interfacial abruptness, and can enhance the localization effect. Temperature- dependent photoluminescence measurements give evidence that the TDs act as nonradiative recombination (NR) centersinInGaNactivelayer.Accordingtotheseresults,itisinferredthattheinﬂuenceofTDontheopticalproperties of InGaN-based QW depends on the competition of localization induced by TDs and the NR effect of TDs. r 2004 Elsevier B.V. All rights reserved. Keywords: A1. High resolution X-ray diffraction; A1. Photoluminescence; A3. Metalorganic chemical vapor deposition; A3. Multi- quantum wells; B1. Nitride 1. Introduction Nitride-based ultraviolet–blue–green light-emit- ting diodes (LEDs) with InGaN/GaN quantum well (QW) as active layers have been successfully developed [1,2].Inspiteofhighdislocationdensities (10 8 –10 10 cm 2 )intheseepilayersgrownon c-plane sapphire substrates, the light emission efﬁciency of thesedevicesisveryhigh.Oneinterpretationisthat threading dislocations (TDs) in GaN and InGaN activelayersdonotactasnonradiativerecombina- tion(NR)centers [3,4].Buttherecentinvestigations with atomic force microscopy (AFM), near-ﬁeld scanning optical microscopy and cathodolumines- cenceimagesofInGaNandGaNindicatethatTDs are NR centers [5–8]. There arise a question that why the dislocations acting as NR centers do not reduce the light emission efﬁciency of the blue LEDs. Thus, the inﬂuence of TDs on emission of InGaN/GaN QW is still in debate. It is signiﬁcant to clarify the role of dislocations on InGaN-based blue LED for future developing such optoelectro- nicsdevices.Toourknowledge,therelationshipof theopticalcharacteristicsofInGaN/GaNQWand TDsatdifferenttemperaturehasnotbeenstudied. In this letter, we report the inﬂuences of TDs on structural and optical properties of InGaN-based blue LED structures. ARTICLE IN PRESS *Corresponding author. Tel.: +86-10-8264-9321; fax: +86- 10-8264-9531. E-mail address: hbyu@aphy.iphy.ac.cn (H.B. Yu). 0022-0248/$-see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2004.02.110