Solvo-thermal synthesis of AlN nano-needles: Their photoluminescence and field emission properties

High density aluminum nitride nano-needles with sharp tips have been synthesized on Si substrate by pre-treating the precursors with aqueous NH3 via facile chemical vapor deposition method without any catalyst. The as synthesized nano-needles have been characterized by XRD, FESEM, EDX, HRTEM and SAED. The observed diameter of the nano-needles is 40-100 nm having sharp tips. The AlN nano-needles exhibited amazing turn-on field of 5.65 V μm−1 (0.01 mA cm−2) at room temperature which is sufficient for electron emission devices, field emission displays and vacuum nano-electronic devices. The room-temperature PL emission peak at 486 nm (2.55 eV) indicates that AlN nano-needles also have potential application in light-emitting nano-device.