ABSTRACT
Benjamin et al. reported that the electron affinity (EA) of AIN and AlxGai_xN (x>0.75) is below zero [1], while Wu et a l reported that EA of AIN is positive 0.6 eV [2]. In any case, EA of AIN is much smaller than that of Si (4.25 eV) and W (4.6 eV). Therefore, AIN is a very promising material for field emission (FE). High FE current density would make possible very thin flat panel displays, so-called field emission display (FEDs), and micro vacuum tubes. However, the current densities so far reported from samples are low [3-5]. We thought that the reasons for low FE current density were that their layers were undoped and low electron density in the layer. Previously, we found that in FE current-voltage characteristics Si doping decreases the threshold voltage [6 ]. The voltage used in [6 ] included voltage drops in the contact and layer resistance, and we explained the Si-doping effect in terms of hopping conduction in the layer and the low electron affinity. The FE current was very stable over time [6 ]. In a basic FED structure, we observed red, green, blue light emission from phosphors excited by field-emitted electrons. The luminance was 1200 cd/cm2 [7].
