Simulations on effects of granular morphology on single-electron and optical spectra of nano- and micro-crystalline AlN and diamond

In the present study, effects of geometry of the granular morphology on particularities of the N(E) distributions and optical absorption spectrum in nominally undoped nano- and micro-crystalline AlN and diamond are simulated within a framework of a semi-empirical adiabatic ‘Generalized Skettrup Model’ (GSM). Obtained simulation results reveal, that alterations in the grain sizes mostly affect relatively deep (i.e. defect) intra-grain states, while band tail electron states are influenced pretty weakly. Amendments in a shape of the crystalline grains also cause considerable alterations in the intra-grain single-electron spectrum of the poly-crystalline layers and powders of AlN and diamond, though such effects are not as strong as the ones that originated from the grain size changes in the range from nano-meters to microns. Results of our semi-empirical simulations match well with corresponding experimental data, previously reported for single-micro- and nano-crystalline AlN and diamond, and might give physically transparent guidelines for adjustment optical and electronic properties of such materials for their various applications.