Planar doping with gallium of molecular beam epitaxial ZnSe

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Abstract
A new approach to doping in ZnSe, which involves Ga deposition in spatially separated atomic planes (planar doping), is reported. The dependence of doping efficiency on the particular surface termination (Zn or Se stabilized) maintained during the deposition of the Ga dopant is investigated by Hall measurements and low-temperature photoluminescence spectroscopy, and the results are compared to those obtained for uniform doping. Under our growth conditions and for the same average amount of Ga atoms arriving at the ZnSe surface, the doping efficiency is dramatically enhanced in the case of Ga planar doping on Zn terminated surfaces. This enhancement correlates with the reduction of the broad deep luminescence bands that dominate under the other doping conditions, indicating an effective reduction of the self-compensating mechanisms. Under optimized conditions, n-type ZnSe with carrier concentration in the 1018 cm−3 range is achieved.