Single phase formation of Co-implanted ZnO thin films by swift heavy ion irradiation: Optical studies

Abstract

Low temperature photoluminescence and optical absorption studies on 200MeV Ag+15 ion irradiated Co-implanted ZnO thin films were studied. The Co clusters present in as implanted samples were observed to be dissolved using 200MeV Ag+15 ion irradiation with a fluence of 1×1012ions∕cm2. The photoluminescence spectrum of pure ZnO thin film was characterized by the I4 peak due to the neutral donor bound excitons and the broad green emission. The Co-doped ZnO films show three sharp levels and two shoulders corresponding to 3t2g and 2eg levels of crystal field splitted Co d orbitals, respectively. The ultraviolet-visible absorption spectroscopy also shows the systematic variation of band gap after 200MeV Ag+15 ion irradiation.

Swift heavy ion induced modifications in cobalt doped ZnO thin films: Structural and optical studies

“…The decrease in band gap is mainly due to the sp-d exchange interaction between the localized d-electrons of Co 2+ ions and band electrons of ZnO [35,36]. Such decrease of band gap due to SHI was also observed in 200 MeV Ag 15+ ion irradiated Co-implanted ZnO thin films [37]. This implies that after SHI irradiation, Co 2+ ions substitute Zn 2+ ions in its wurtzite lattice structure which is also consistent with the result of optical transmission spectra.…”

Microstructural, magnetic and optical characterizations of nanocrystalline Zn1−xMnxO dilute magnetic semiconductors synthesized by mechanical alloying

“…The II-VI, III-V group elements are the most studied materials. Enormous application of spintronic devices such as spin-valve transistor, spinlight emitting diodes, non-volatile memory, optical isolator and ultra fast optical switches inspired widespread research work to synthesize the DMS with II-VI and III-V semiconductors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Among these materials, Mn doped II-VI and III-V semiconductors have been well studied, particularly the Mn doped GaAs [4,5].…”

“…The ZnO based DMS systems have some unique characteristics like large band gap (∼3.37 eV), large exciton binding energy at room temperature (∼60 meV), high optical gain (300 cm −1 ), very short luminescence life time [1] which are required for various optoelectronic [2] and magneto-optical [3] devices.…”

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

“…Theoretical calculations by Sako and Katayama-Yoshida [5], have predicted that intrinsic FM of Co doped ZnO can be achieved by electrondoping, when magnetic dopants substituted at 'Zn' cation sites. There are few reports with experimental results on Co doped ZnO with DMS properties [6][7][8][9][10][11][12][13][14][15][16][17]. But the possibilities of extrinsic FM have not been ruled out, in fact it has been observed in Co doped ZnO [18][19][20][21], due to the formation of metallic Co impurity, Co 3 O 4 phases and oxygen vacancies.…”