Observation of the amorphous zinc oxide recrystalline process by molecular dynamics simulation

Abstract

The detailed structural variations of amorphous zinc oxide (ZnO) as well as wurtzite (B4) and zinc blende (B3) crystal structures during the temperature elevation process were observed by molecular dynamics simulation. The amorphous ZnO structure was first predicted through the simulated-annealing basin-hopping algorithm with the criterion to search for the least stable structure. The density and X-ray diffraction profiles of amorphous ZnO of the structure were in agreement with previous reports. The local structural transformation among different local structures and the recrystalline process of amorphous ZnO at higher temperatures are observed and can explain the structural transformation and recrystalline mechanism in a corresponding experiment [Bruncko et al., Thin Solid Films 520, 866-870 (2011)].

Self‐Directed Localization of ZIF‐8 Thin Film Formation by Conversion of ZnO Nanolayers

“…For the estimation of the density of the thin film it was assumed that the reported density value for bulk ZIF‐8 is also valid for thin films of the same type of material. The densities (ρ) of the ALD[31a] and sputtered ZnO are 4.47 g cm −3 and 5.61 g cm −3 and the theoretical density of crystalline ZIF‐8[31b,c] is 0.95 g cm −3 giving γ = 21.2 and 16.9, respectively. The factors can be used for the estimation of the resulting ZIF‐8 film thickness.…”

Density functional theory model of amorphous zinc oxide (a-ZnO) and a-X0.375Z0.625O (X= Al, Ga and In)

“…The coordination number for Zn and O expressed in percentage, average coordination number and the DFT-GGA energy for a-ZnO model. The coordination number for Zn are compared with the other MD model[2]. As expected there are a few more coordination defects in the more rapidly quenched model 2.…”

“…We have prepared a model by using the melt-quench method. For a-ZnO, the system consists of 128 atoms in a cubic box of length 12.34 Å corresponding to the experimental density of 4.6 g/cm 3 [2]. The random starting configuration is equilibrated at 5000 K is cooled to 3000 K at 100 K/ps followed by an equilibration of 5 ps.…”

“…Crystalline ZnO has important application as a piezoelectric material and due to its property of being transparent in visible light [1]. It has a wide direct band gap (∼ 3.37 eV at 300 K) which makes it a promising candidate for optoelectronic devices [1,2]. Therefore, there has been a wealth of experimental work in crystalline ZnO (a-ZnO).…”

Non-classical nucleation of zinc oxide from a physically-motivated machine-learning approach

“…The disordered structures are collected along short high-temperature MD runs with no further relaxation as to produce non-vanishing forces on all ions. For those first MD runs, we use a classical Buckingham ZnO potential [99] which was previously employed in numerous studies of ZnO [100][101][102][103]. We would like to emphasize that using a classical potential instead of firstprinciple calculations at this stage favors a more rapid sampling of a larger variety of configurations.…”