A display-type analyzer with +/- 20 degrees acceptance angle and high-energy resolution has been applied to analysis of the operation mechanism in a nanocrystalline polysilicon quasiballistic emitter. Angle-resolved emission patterns and the corresponding energy distributions are measured as a function of the applied device voltage in the range from 10 to 20 V. The experimental data suggest that there are two kinds of emission band in the energy spectra. The one emission peak at lower energies exhibits definitely directional features, whereas a significantly large angular dispersion is observed in another emission peak at higher energies. The intensity of the latter emission band becomes dominant in the range of the applied device voltage higher than 15 V. These results can be explained from the correlation between the silicon nanostructure in the device and the major carrier transport mode there. The analysis presented here supports the previously proposed model that the quasiballistic emission is based on the field-induced generation of energetic electrons in nanocrystalline silicon diode. (C) 2008 American Vacuum Society. [DOI: 10.1116/1.2975203]