Field emission from GaN/AlN nano-films on Si substrate prepared by pulsed laser deposition

GaN/AlN two-layer films with different thickness are synthesized on Si substrates by pulsed laser deposition (PLD). GaN and AlN single-layer films are also synthesized for comparison. It is found that the turn-on field of the GaN/AlN two-layer films are considerably decreased 2 orders of magnitude than that of single-layer films. The improvement of FE characteristics an attributed to the quantum structure effects, which supplies a favorable location of electron emission and enhances tunneling ability. We show that by tuning the thickness of GaN/AlN, various FE characteristics can be obtained, which is induced by the modulation of quantum potential well/barrier structure. It indicates that an optimal thickness exists for GaN/AlN two-layer nano-films to give best field emission performance.