The kinetics of the growth of nitrogen-doped ZnSe grown by photo-assisted MOVPE

Detailed growth kinetic studies of the photo-assisted growth of ZnSe from the precursors dimethylzinc triethylamine adduct (DMZn.TEN) with either dimethylselenium (DMSe) or diethylselenium (DESe) have shown that there are two regimes of growth temperature, low temperature growth dominated by site blocking from unreacted precursors and a high temperature regime dominated by precursor desorption. The proposed growth mechanism is based on a surface bimolecular reaction mediated by hydrogen radicals which is initiated by the decomposition of surface DMZn. The same mechanism has been used to explain the residual hydrogen concentration in the DMSe grown layers of 1 × 10¹⁷ cm⁻³ and the enhancement in hydrogen incorporation that occurs with DESe by deviating from 1:1 precursor ratio. Nitrogen doping using trimethylsilylazide (TMSiN₃) in combination with DESe has achieved nitrogen incorporation up to 1 × 10²⁰ cm⁻³ but the incorporation of hydrogen is also observed to increase and the growth rate decrease. This has been explained using a Langmuir Hinshelwood model causing a disruption of the surface bimolecular reaction and bonding hydrogen radicals to surface nitrogen.