Conventional　metal　oxide　semiconductor　(MOS)　gas　sensors　have　been　investigated　for　decades　to　protect　our　life　and　property.　However,　the　traditional　devices　can　hardly　fulfill　the　requirements　of　our　fast　developing　mobile　society,　because　the　high　operating　temperatures　greatly　limit　their　applications　in　battery-loaded　portable　systems　that　can　only　drive　devices　with　low　power　consumption.　As　ammonia　is　gaining　importance　in　the　production　and　storage　of　hydrogen,　there　is　an　increasing　demand　for　energy-efficient　ammonia　detectors.　Hence,　in　this　work,　a　Schottky　diode　resulting　from　the　contact　between　zinc　oxide　nanorods　and　gold　is　designed　to　detect　gaseous　ammonia　at　room　temperature　with　a　power　consumption　of　625　μW.　The　Schottky　diode　gas　sensors　benefit　from　the　change　of　barrier　height　in　different　gases　as　well　as　the　catalytic　effect　of　gold　nanoparticles.　This　diode　structure,　fabricated　without　expensive　interdigitated　electrodes　and　displaying　excellent　performance　at　room　temperature,　provides　a　novel　method　to　equip　mobile　devices　with　MOS　gas　sensors.