A composition including a polycrystalline metal nitride having a number of grains is provided. These grains have a columnar structure with one or more properties such as, an average grain size, a tilt angle, an impurity content, a porosity, a density, and an atomic fraction of the metal in the metal nitride. An apparatus for preparing a metal nitride is provided. The apparatus may include a housing having an interior surface that defines a chamber and an energy source to supply energy to the chamber. A first inlet may be provided to flow a nitrogen-containing gas into the chamber. Raw materials may be introduced into the chamber through a raw material inlet. A second inlet may be provided to flow in a halide-containing gas in the chamber. The apparatus may further include a controller, which communicates with the various components of the apparatus such as, sensors, valves, and energy source, and may optimize and control the reaction.