title: Photoluminescence studies of 100 MeV Ni8+ ion irradiated Al2O3 single crystals.
abstract: We present the results of photoluminescence (PL) measurements on 100 MeV Ni(8+) ion irradiated Al(2)O(3) single crystals in the fluence range 1x10(11) to 5x10(12) ions/cm(2). A sharp PL peaks at approximately 693, 695, 707 and 730 nm are recorded with an excitation of 442 nm He-Cd laser beam. The sharp emission peaks at 693 and 695 nm are attributed to R(2) and R(1) lines of Cr(3+) ions, and they are related to the transition from (2)E(g)-->(4)A(2g). The weaker sharp peaks called N lines appear at approximately 707 nm and its origin is ascribed due to closely coupled pairs of Cr(3+) ions. The longer wavelength part of the PL spectra at approximately 730 nm may be due to increase of groups of more than two Cr(3+) ions. It is observed that the broad emission band (450-650 nm) consists of four bands centered at 470, 518, 547 and 618 nm, respectively. The 470, 518 and 547 nm bands are corresponding to F(2)(+), F(2) and F(2)(2+) defect center, respectively. It is observed that the PL intensity of F(2), F(2)(2+), R and N lines increases with Ni(8+) ion fluence. This can be attributed to increase in concentration of color centers responsible for luminescence through radiative recombination.
authors.affiliation: Department of PG Studies in Physics, Govt. Science College, Tumkur 572 103, India. bhushanvl@rediffmail.com
authors.forename: H
authors.initials: H
authors.lastname: Nagabhushana
authors.forename: B
authors.initials: B
authors.lastname: Umesh
authors.forename: B M
authors.initials: BM
authors.lastname: Nagabhushana
authors.forename: B N
authors.initials: BN
authors.lastname: Lakshminarasappa
authors.forename: Fouran
authors.initials: F
authors.lastname: Singh
authors.forename: R P S
authors.initials: RP
authors.lastname: Chakradhar
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D003460:Crystallization; D008163:Luminescent Measurements / Q000379:methods*; D009532:Nickel / Q000737:chemistry; D010777:Photochemistry
chemical_list: D002412:Cations; D009532:Nickel; D000537:Aluminum Oxide