Growth and characterization of liquid−phase epitaxial In<i>x</i>Ga1−<i>x</i>As

Abstract

The liquid−phase epitaxial growth of InxGa1−xAs (0&amp;lt;x≲0.15) single and multiple layers on GaAs substrates has been studied. Growth on 111B−oriented substrates results in planar interfaces, although it requires careful control of the growth temperature relative to the liquidus temperature. For this reason, detailed liquidus and solidus data along the 850 °C isotherm have been determined for the In−rich corner of the In−Ga−As system. The phase diagram of the system has been calculated and found to be in satisfactory agreement with the measurements. An accurate determination of the room−temperature band gap of InxGa1−xAs as a function of x has been made using photoreflectance and photoluminescence techniques. The room−temperature electrical properties of doped layers also have been measured, and Zn acceptors and Se or Te donors were found to be useful dopants. Ge was found to be an amphoteric dopant; it is an acceptor for x≲0.07 and otherwise a donor. By making use of stepwise compositionally graded lattice−matching layers between the substrate and the p−n homojunction, In0.15Ga0.85As light−emitting diodes with total external room−temperature efficiencies ∼1% have been fabricated.