Thermal stability of ion-implanted ZnO

Abstract

Zinc oxide single crystals implanted at room temperature with high-dose (1.4×1017cm−2) 300 keV As+ ions are annealed at 1000–1200 °C. Damage recovery is studied by a combination of Rutherford backscattering/channeling spectrometry (RBS/C), cross-sectional transmission electron microscopy (XTEM), and atomic force microscopy. Results show that such a thermal treatment leads to the decomposition and evaporation of the heavily damaged layer instead of apparent defect recovery and recrystallization that could be inferred from RBS/C and XTEM data alone. This study shows that heavily damaged ZnO has relatively poor thermal stability compared to as-grown ZnO which is a significant result and has implications for understanding results on thermal annealing of ion-implanted ZnO.

Ion-implantation induced nano distortion layer and its influence on nonlinear optical properties of ZnO single crystals

“…3 In particular, as a well-established technique for modifying properties of semiconductors, ion-implantation has been used to manipulate the electric and thermal characters of ZnO, as well as its crystal structure and defect properties. [4][5][6][7][8] As a standard second-order nonlinear optical process, second harmonic generation (SHG) has been increasingly studied in ZnO bulk crystals and nanostructures. [9][10][11][12][13] However, to the best of our knowledge, there have been no reports about the study of nonlinear optical properties and X-ray diffraction (XRD) rocking curves of ionimplanted ZnO single crystals.…”

“…The total diffracted amplitude is then the sum of coherently interfering functions of the type shown in Eqs. (6), adjusted for phase lags and normal absorption during traversal through the crystal. Although usually extinction is stronger than normal absorption, for depth-dependent strain distributions the latter can be more important, which is the case of ion-implanted crystals.…”

Crystallographically oriented Zn nanocrystals formed in ZnO by Mn+-implantation

“…1͑a͒ and 1͑c͔͒. The first layer extends from the surface to a depth of ϳ80 nm, where ϳ20-50 nm diameter voids or gas bubbles 9,10 are formed, and the surface of the sample is rough. Below this layer, the underlying layer extends to a depth of ϳ160 nm where the corresponding EFTEM mappings ͓Figs.…”

In-implanted ZnO: Controlled degenerate surface layer

“…However, the main disadvantage of II is that high annealing temperatures are usually necessary to reduce lattice damage caused by the implantation, and these high temperatures sometimes alter the dopant profile and lead to other deleterious effects. 2,3 The rule of thumb is that the required annealing temperature T A,crit should be about 2 / 3 of the melting temperature, and this would give a T A,crit of about 1275°C in ZnO. Unfortunately, some researchers found that even lower annealing temperatures of 1000-1200°C can actually cause a heavily damaged implanted layer to partially or totally evaporate, 3 which would seem to limit applications of II in ZnO.…”

“…2,3 The rule of thumb is that the required annealing temperature T A,crit should be about 2 / 3 of the melting temperature, and this would give a T A,crit of about 1275°C in ZnO. Unfortunately, some researchers found that even lower annealing temperatures of 1000-1200°C can actually cause a heavily damaged implanted layer to partially or totally evaporate, 3 which would seem to limit applications of II in ZnO. Still, about 300 papers on this subject have been published so far, according to the ISI Web of Science.…”