Nitrogen-doped ZnSe with selenium-rich growth by low-pressure organometallic chemical vapor deposition

Abstract

A high-quality nitrogen-doped p-type ZnSe epilayer on (100) GaAs substrate was obtained under selenium-rich growth conditions by low-pressure organometallic chemical vapor deposition. Ammonia was used as the dopant source. The resistivity (0.5 Ω cm) and the free-carrier concentration (p=8.8×1017 cm−3) of as-grown ZnSe:N were derived from Hall measurements. With selenium-rich growth conditions, we can reduce the concentration of compensation defects (VSe-Zn-NSe which acts as a donor in ZnSe). Nitrogen is found to incorporate in ZnSe as a shallow level, which is examined by the dependence of free-to-acceptor emission on the NH3/H2Se molar ratio. The carrier concentration of as-grown ZnSe:N seems to change insignificantly within a wide range of growth temperatures. That is thought to be useful for device fabrication due to uniformity considerations.