Comparison of hydrogen passivation of ZnSe:N using gas source and conventional molecular beam epitaxy

Abstract

The use of various gaseous source epitaxial techniques for the growth of II–VI compounds, such as metalorganic vapor phase epitaxy (MOVPE) or gas source molecular beam epitaxy (GSMBE), offers the promise of improved flux control and source flexibility. However, passivation of the nitrogen acceptors by hydrogen (which is usually present in abundance in these growth environments) has proven to be a major obstacle in the successful application of MOVPE and GSMBE for the growth of highly conductive p-type ZnSe. Although there have been a few reports of successful nitrogen doping of ZnSe:N by GSMBE and MOVPE, the mechanisms of hydrogen incorporation, and its dependence on the growth conditions as well as post-growth treatments, are still unclear. In this paper, we will compare the hydrogen passivation behavior in ZnSe:N grown by: (1) GSMBE using H2Se and elemental Zn as sources; and (2) conventional molecular beam epitaxy (MBE) with intentional introduction of hydrogen. A comparison of the electrical properties existing between the GSMBE-grown ZnSe:N films with those grown by MBE with an intentional flux of hydrogen will be presented.