ELECTRICAL CHARACTERIZATION OF DOPED ZNSE-BASED HETEROSTRUCTURES GROWN BY MOVPE

The electrical characterization of Cl- or N-doped layers in the ZnMgSS e material system is reported. We used biscyclopentadienylmagnesium, d imethylzinc-triethylamine, tertiary-butylthiol, diisopropylselenide an d ditertiarybutylselenide to grow layers by metalorganic vapor phase e pitaxy at various low growth temperatures (330-440 degrees C). Capacit ance-voltage profiling, current-voltage, Hall, and transient photocapa citance measurements in conjunction with photoluminescence spectra wer e used to verify the layer properties. With intentional chlorine dopin g using 1-chlorobutane, free electron concentrations of up to 2 X 10(1 8) cm(-3) in ZnSe and 1 x 10(17) cm(-3) in ZnSxSe1-x (x = 4%) have bee n achieved. All C-V measurements on ZnSe:N doped with bistrimethylsily lamidozinc, trimethylsilylazide, or triallylamine show n-type or semi- insulating behavior, although PL spectra show acceptor-bound excitons and DAP recombinations. Compensation due to incorporated hydrogen orig inating from the precursor is assumed, besides a background chlorine c ontamination. However, Hall measurements of several samples doped with BTM and TAN indicate p-type conduction. Maximum hole concentrations o f 5 x 10(17) cm(-3) and Hall mobilities of 30 cm(2)/V . s were measure d. Transient photocapacitance measurements confirm the presence of tra ps with very long time response, probably at the Au/ZnSe interface.