26 Journal of Crystal Growth 81(1987) 26—33 North-Holland, Amsterdam A COMBINED COMPUTER SIMULATION, RHEED INTENSITY DYNAMICS AND PHOTOLUMINESCENCE STUDY OF THE SURFACE KINETICS CONTROLLED INTERFACE FORMATION IN MBE GROWN GaAs/A1~Ga 1 1As(100) QUANTUM WELL STRUCTURES * A. MADHUKAR, P. CHEN **, F. VOILLOT ‘~‘, M. THOMSEN, J.Y. KIM, W.C. TANG and S.V. GHAISAS Department of Materials Science, University of Southern California, Los Angeles, California 90089-0241, USA We report some illustrative results of a multi-pronged approach to examining the connection between the chosen growth condition dependent surface kinetics and the nature and consequences of the resulting interfaces in MBE grown GaAs/Al~Gai _~As(1OO)ultra-thin quantum well structures. The approach involves (i) computer simulations of the MBE growth process, (ii) systematic measurements of the RHEED intensity behavior of static and dynamic surfaces as a function of both, the diffraction and growth conditions, (iii) growth of quantum well structures under conditions indicated by combination of (i) and (ii) to imply specific behavior of interfaces, and (iv) their examination via photoluminescence and excitation spectra studies. A connection between these aspects is thus established for the first time. 1. Introduction many consequences for the nature and mechanism of MBE growth as a function of the user con- This paper provides a brief report on our ef- trolled parameters (substrate temperature (1~), forts to examine the underlying interconnection group V pressure ~ growth rate (T111) and between the growth condition controlled surface alloy composition) have been examined [3—7]. kinetic processes, the resulting structural and Since the computer simulations provide the dy- chemical nature of the growth front, its conse- namics of the growth front evolution and forma- quences for the formation of interfaces, and their tion of interfaces through such characteristics as influence on the properties of the resulting quan- the step density distribution, the terrace width turn well structures in molecular beam expitaxial distribution, the nature of chemical distribution in growth. This multi-pronged approach to address- alloys, etc., the behavior of many of these growth ing such issues has involved fairly detailed and kinetics dependent features lends itself to an ex- sophisticated computer simulations [1—7]of the amination via comparison of their calculated con- MBE growth process based upon information sequences with experiments capable of probing available on the surface kinetic processes of ad- the same. Reflection high-energy electron diffrac- sorption, desorption, migration and dissociative tion (RHEED) is one such technique sensitive to molecular reaction involved in growth of Ill—V the structural aspects. Consequently, detailed and materials. The resulting growth process has been systematic measurements [8—13]of the RHEED identified [1—3]as a configuration-dependent reac- intensity behavior of static, dynamic and relaxing tive-incorporation (CDRI) growth process and its surfaces involved in GaAs/Al~Ga1 - As(100) quantum wells and their comparison with the * Work supported by AFOSR and ONR. CDRI model based findings of the computer ** Permanent address: Physics Department, Fudan Univer- simulations constitute the second major ingredient sity, Shanghai, People’s Rep. of China, of our approach. Such comparative studies have ~ Permanent address: INSA, Département de Genie begun to provide a basis for usage of RHEED as a Physique, F-31077 Toulouse Cedex, France. ~ Permanent address: Physics Department, Poona Univer- fundamental and pragmatic technique for identify- sity, Pune, India. ing ranges of growth conditions which, from an 0022-0248/87/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)