Effects on the resonant tunneling characteristics of a double-barrier diode of intentional and unintentional dopings in the quantum well

Donor-assisted resonant tunneling in nominally symmetric GaAs/(AlGa)As large area double-barrier diodes is investigated. The log(I)–V characteristics are used to evaluate doping density in the quantum well and are investigated in connection with donor cluster-assisted resonant tunneling. The single-donor-related feature in the resonant-tunneling characteristics is used to detect the presence of donors in the quantum well, even at concentrations of the order of the lowest achieved so far in molecular beam epitaxy GaAs. Expected effects of the presence of donors in the quantum well on the log(I) vs V characteristics are discussed.