GROWTH AND PROPERTIES OF GRADED BAND-GAP ALXGA1-XAS LAYERS

Graded band-gap AlxGa1-xAs layers were grown using isothermal LPE techniques together with undersaturated solutions. The layer thicknesses were 1500-2500 Å and the value of x in the graded layers increased monotonically to ≈0.8 at the surface. The Al depth profiles, as measured by Auger analyses, are in good agreement with those derived by assuming rapid Al diffusion through the liquid boundary layer resulting from partial dissolution of the substrate surface. It was found that the graded-layer thickness could be controlled by varying the degree of undersaturation of the solution at any given temperature.