NITROGEN AS CARRIER GAS FOR THE GROWTH OF ZNSE AND ZNSEN IN PLASMA-ENHANCED METALORGANIC VAPOR-PHASE EPITAXY

For the precursor combination dimethylzinc-triethylamine and ditertiar ybutylselenide the use of nitrogen carrier gas was investigated for th e metalorganic vapor phase epitaxy (MOVPE) of ZnSe and ZnSe:N. The nit rogen doping was carried out with a separate nitro en flow which was a ctivated by a de-plasma. In the photoluminescence spectra of undoped l ayers grown at 340 degrees C with a VI/II ratio of 0.18 only excitonic emissions, separated into free and donor bound excitons, can be obser ved. The background carrier concentration was of the order of 1 x 10(1 6) cm(-3). The growth rate of epilayers grown in nitrogen is reduced b y about 75% in comparison to the value obtained by using hydrogen as c arrier gas. The doping can be regulated by the dopant flow and by the total pressure in the reactor. With increasing flow of plasma activate d nitrogen and a reduced total pressure, the PL spectra showed broaden ed DAP emission without excitonic emissions. The electrical and optica l properties obtained with nitrogen carrier gas are comparable with th e results obtained with hydrogen carrier gas. So far, no p-type conduc tivity was measured. Therefore, the problem of compensation of p-type conductivity of ZnSe:N doped by de-plasma enhanced N-2 was not solved by the use of N-2 carrier gas.