ISOTHERMAL LPE GROWTH OF THIN GRADED BAND-GAP ALXGA1-X AS LAYERS

Liquid-phase-epitaxial growth experiments, using saturated Ga-Al-As solutions and GaAs substrates, were carried out under isothermal conditions. It was found that graded band-gap AlxGa1-xAs growth occurs under these conditions. The layer thicknesses were between 400 and 700 Å and the Al composition in the layer increased monotonically toward the surface. When a saturated Ga-As solution was brought into the contact with an Al xGa1-xAs solid and held at constant temperature, partial dissolution of the AlxGa1-xAs was observed. The resulting processes of compositional graded growth or partial dissolution follow from thermodynamic nonequilibrium between solid and liquid. It can be expected that similar processes will occur in other AIII-BIII-C V systems.