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 larg e area double-barrier diodes is investigated. The log(I)-V characteristics are used to evaluate doping density in the quantum well and are investigate d 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 o f the order of the lowest achieved so far in molecular beam epitaxy GaAs. E xpected effects of the presence of donors in the quantum well on the log(I) vs V characteristics are discussed. (C) 1999 American Institute of Physics . [S0021-8979(99)03914-6].