Surface ZnSe:Ca layers with hole conductivity

The authors investigate the effect of treating n-ZnSe substrates with boiling aqueous Ca(NO3)2 suspension on their electrical and luminescent properties. Base substrates were cut from bulk pure zinc selenide crystals grown from a stoichiometric melt by the Bridgman method. It was found that the Ca-doping of the substrates causes an almost complete “quenching” of the low-energy orange emission band with a maximum near ħωmax ≈ 1,95 eV and a significant increase in the efficiency of the edge blue luminescence band.

The origin of luminescence from di[4-(4-diphenylaminophenyl)phenyl]sulfone (DAPSF), a blue light emitter: an X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) study

The blue luminescence band of DAPSF is primarily associated with the sulfur functional group.

Photoluminescence Study of Damage Introduced in GaN by Ar- and Kr-Plasmas Etching

ABSTRACTWe investigated, by employing a photoluminescence technique, the etching damage introduced in near-surface regions of GaN by Ar and Kr plasmas and clarified the differences between the damage characteristics of these regions for the two plasma etching cases. For Ar plasma, the shallow donor-acceptor pair emission at ~3.28 eV was significantly weakened; additionally, a broad blue luminescence band arose at approximately ~3.0 eV. In contrast, for Kr plasma under high gas pressure, we found the recovery of the damage to the same level as the as-grown crystallinity. These differences in the damage characteristics for the two plasma etching cases probably depend upon which atom (N or Ga) is preferentially etched in these cases.

A VERSATILE APPROACH FOR THE SYNTHESIS OF ALUMINUM OXIDE NANORODS BASED ON A SIMPLE REACTION

Aluminum oxide (α -Al 2 O 3) nanorods have been successfully synthesized by a simple reaction of aluminum powder with water without any additives/organics at 100°C. This is the first report for the synthesis of aluminum oxide nanorods where water has been used as solvent as well as a source of oxygen. The diameters of nanorods are relatively uniform, ranging from 40–60 nm with length of several micrometers. A plausible mechanism is proposed for the formation of these nanorods and is expected that this synthetic technique can be extended to obtain other metal oxides. Photoluminescence measurements reveal a blue luminescence band with two peaks at 310 and 420 nm, which could be attributed to F + centers. The reported method is new, economical, fast and free of pollution, which will make it suitable for large scale production.