Determination of the electron concentration and mobility in the vicinity of a quantum well and δ-doped layer in InGaAs/GaAs heterostructures

Abstract

Comparative admittance measurements in mesadiodes on an n+-GaAs substrate and in ring planar diode structures on an i-GaAs substrate, which contain a Si δ-doped layer and an InGaAs quantum well in the GaAs epitaxial layer are performed. The possibility of determining the concentration profile and electron mobility in the vicinity of the δ-doped layer and the InGaAs quantum well is shown based on an analysis of the simultaneously measured capacitance-voltage and conductance-voltage characteristics of the mesadiodes. By performing such measurements for i-GaAs-based ring diode structures with the given geometry, it is possible to reliably determine only the concentration profile. The influence of the relative location of the quantum well and δ-doped layer on the concentration profile and mobility is revealed. The phenomenon of Maxwell relaxation in i-GaAs-based ring diode structures is discussed.