Determination of the conduction-band discontinuities of GaAs/Al<i>x</i>Ga1−<i>x</i>As interfaces by capacitance-voltage measurements

Abstract

The relation between the conduction-band discontinuity ΔEc and the Al composition x of refined GaAs/AsxGa1−xAs (x&amp;lt;0.42) heterointerfaces was determined by means of capacitance-voltage measurements. The resulting relation, ΔEc=0.67ΔEg, is different from Dingle’s rule. The interface charge density σ of a series of the samples was also investigated in relation to the reliability of the determination of ΔEc. It was found that σ less than 1×1011/cm2 is required to determine ΔEc with the precision of ±10 meV.