New and improved gain materials for solid-state high power and high energy lasers are highly sought. GaN satisfies many of the criteria of an excellent lasing gain medium including its higher thermal conductivity and lower thermal expansion coefficient than traditional gain materials such as yttrium aluminum garnet (YAG) crystals doped with neodymium emitting 1.06 μm wavelength. Single crystals of erbium doped GaN (Er:GaN) thick layers have been successfully synthesized by hydride vapor-phase epitaxy. By utilizing a thin GaN epilayer grown on c-plane sapphire using metal organic chemical vapor deposition as a template and varying growth parameters including the NH3 flow rate, thick layers of Er:GaN which exhibit the desired Er3+ related emission at 1.54 μm window at room temperature have been realized for the first time. The work opens up the feasibility to utilize Er:GaN bulk crystals as a gain medium for next generation solid-state high power and high energy lasers operating in the eye-safer 1.5 μm window.