Electroreflectance and photoluminescence study of the effect of hydrogen on heavily doped GaAs/AlGaAs structures

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Abstract
Highly doped semiconducting heteroepitaxial structures are commonly found in advanced devices. It is difficult to interpret quantitatively the results of optical measurements on such structures because the strong built‐in electric fields present invalidate the low‐field theories usually used to interpret those results. We have studied by electrolyte electroreflectance and photoluminescence a GaAs/AlGaAs resonant tunneling structure with a highly n‐doped GaAs substrate and cap, before and after hydrogenation. We also have developed a new, improved microscopic theoretical treatment of the effects of strong fields on the local dielectric function and have used that treatment to evaluate quantitatively the effect of hydrogenation on the densities of shallow donor levels and of deep traps in the GaAs cap and to find the interface charges and band‐pinning levels in the resonant tunneling junction.