A quantum wire device includes a barrier formed by an insulator or a wide bandgap semiconductor, and metal quantum wires comprising a metal material and embedded in the barrier. Potential wells are formed for electrons in the metal quantum wires by the insulator or the wide bandgap semiconductor. The work function of the metal quantum wires is reduced by quantum confinement compared to a bulk form of the metal material. The metal quantum wires are electrically connected. The metal quantum wires include an exposed active area for electron emission or electron collection.