Gated diamond field emitter arrays with ultralow operating voltage and high emission current have been developed. Two types of built-in gated diamond field emitters have been successfully fabricated : (i) a gated structure created by molding and self-align technique, and (ii) a cap-gated structure created by molding and electrostatic bonding. Depending on the diamond tip＇s composition and surface treatment, high emission current at very low operating voltage (varying from <10 V to >10 V) can be designed to meet various applications. The built-in gated diamond tips have a stable emission current at a fixed gate voltage. Current fluctuation is found to be about 1.1% for low emission current and less than 10% for higher emission current. Emission stability is considerably more stable than silicon emitters.