Journal of Luminescence 102–103 (2003) 455–459 Origin of white color light emission in ALE-grown ZnSe M. Godlewski a, *, E. Guziewicz a , K. Kopalko a , E. Lusakowska a , E. Dynowska a , M.M. Godlewski b , E.M. Goldys c , M.R. Phillips d a Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland b Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agriculture University, Warsaw, Poland c Semicond. Science and Technology Laboratory, Macquarie University, North Ryde 2109 NSW, Australia d Microstructural Analysis Unit, University of Technology, Sydney, Australia Abstract We discuss light emission properties from thin films of ZnSe grown by atomic layer epitaxy on GaAs (1 0 0). White color emission is observed in photoluminescence and cathodoluminescence, due to the observation of three RGB emission bands. We demonstrate possibility of color tuning by either variation of film thickness or, in cathodoluminescence experiments, variation of an accelerating voltage. r 2002 Elsevier Science B.V. All rights reserved. PACS: 81.15.Cd; 78.66.Hf; 78.60.Hk; 68.37.Hk Keywords: White light emission; ZnSe; Atomic layer epitaxy; Cathodoluminescence 1. Introduction It is expected that conventional white light sources will soon be replaced by a new generation of semiconductor-based white light emitting de- vices. Recently, InGaN-based white light emitting diode (LED) was commercialized [1] for use both as common overhead lightning and as back lighting in LCD displays [2]. AlGaInN single QW structures with tricolor RGB converters [3], homoepitaxial ZnSe-based LED’s [4,5], combining blue-green color emission from ZnCdSe QWs with a yellow emission from ZnSe substrate, and full- color ZnCdMgSe/ZnCdSe light emitting diodes [6] were also tested as sources of white color emission. In this article we discuss white color emission from thin films of ZnSe grown by atomic layer epitaxy (ALE), which may be suitable for some applications, e.g., in thin film electroluminescence for flat full color display applications [7]. 2. Samples ZnSe samples were grown using atomic layer epitaxy (ALE) [7,8] in F-120 reactor of Micro- chemistry in a gas flow environment. The films were grown from elemental Zn metal and selenium precursors on (1 0 0) oriented, uncoated GaAs substrates treated in NH 4 OH prior to the growth. We used nitrogen gas as a transport gas. Further *Corresponding author. Tel.: +48-22-843-68-61; fax: +48- 22-843-09-26. E-mail address: godlew@ifpan.edu.pl (M. Godlewski). 0022-2313/02/$ - see front matter r 2002 Elsevier Science B.V. All rights reserved. doi:10.1016/S0022-2313(02)00597-5