Multiple chamber molecular beam epitaxy growth system: Growth of GaAs/ZnSe heterostructures

A multiple chamber molecular beam epitaxy (MBE) system has been used to investigate a novel material system: GaAs/ZnSe heterostructures. Growth of ZnSe on GaAs shows that two dimensional nucleation of ZnSe occurs only on As rich GaAs surfaces while island growth occurs on the Ga rich surfaces. Studies of the inverted interface, GaAs on ZnSe, reveal a special disorder and roughening at the interface. These results are explained as manisfestations of the electronic imbalance which exists at the ZnSe/GaAs interface. Also, improved ZnSe crystalline quality is achieved by the incorporation of thin epitaxial layers of AlAs or InGaAs between the GaAs substrate and the ZnSe layer. Finally, an assessment of the interface quality resulting from the transfer between growth chambers confirms that extremely high quality interfaces can be obtained by this multiple chamber process.