Electrical characterization of doped ZnSe-based heterostructures grown by MOVPE

The electrical characterization of Cl- or N-doped layers in the ZnMgSSe material system is reported. We used biscyclopentadienylmagnesium, dimethylzinc-triethylamine, tertiary-butylthiol, diisopropylselenide and ditertiarybutylselenide to grow layers by metalorganic vapor phase epitaxy at various low growth temperatures (330-440 degrees C). Capacitance-voltage profiling, current-voltage, Hall, and transient photocapacitance measurements in conjunction with photoluminescence spectra were used to verify the layer properties. With intentional chlorine doping using 1-chlorobutane, free electron concentrations of up to 2 X 10(18) cm(-3) in ZnSe and 1 x 10(17) cm(-3) in ZnSxSe1-x (x = 4%) have been achieved. All C-V measurements on ZnSe:N doped with bistrimethylsilylamidozinc, 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 originating from the precursor is assumed, besides a background chlorine contamination. However, Hall measurements of several samples doped with BTM and TAN indicate p-type conduction. Maximum hole concentrations of 5 x 10(17) cm(-3) and Hall mobilities of 30 cm(2)/V . s were measured. Transient photocapacitance measurements confirm the presence of traps with very long time response, probably at the Au/ZnSe interface.