B.J. Sun

Structure and magnetic properties of Mn-doped ZnO nanoparticles

We report the crystal structure and magnetic properties of the Zn1-xMnxO compounds synthesized by a combustion method. The Zn1-xMnxO compounds with x=0-0.1 crystallize in the wurtzite ZnO structure. The lattice parameters a and c of Zn1-xMnxO increase linearly with the Mn content, indicating that Mn2+ ions substitute for Zn2+ ions. Scanning electron microscopy shows that the average particle radius of Zn0.95Mn0.05O is about 40 nm. From the Curie-Weiss behavior of susceptibility at high temperature, it was found that the Mn-Mn interaction is dominated by antiferromagnetic coupling with effective nearest-neighbor exchange constant J about -32 K and the large negative value of the Curie-Weiss temperature

Visible and infrared emissions from c-axis oriented AlN : Er films grown by magnetron sputtering

Visible and infrared photoluminescence was observed from AlN:Er films grown by reactive radio-frequency magnetron sputtering under different powers. X-ray diffraction indicates that the films have a c-axis oriented hexagonal wurtzite structure with an average crystallite size of about 59-83 nm and a strain of about (1.12-1.69) x 10(-3). Green emissions (similar to 540 and 558 nm) from the AlN: Er films are due to the intra-4f(n) transition of Er3+ from H-2(11/2) and S-4(3/2) to I-4(15/2), and infrared (similar to 1535 nm) emissions correspond to I-4(13/2) to I-4(15/2) transitions. Increasing the sputtering power results in larger grain size, lower strain, and enhancement of the luminescence intensity. (c) 2006 American Institute of Physics.

Structure and visible photoluminescence of Sm3+, Dy3+and Tm3+ doped c-axis oriented AlN films

Visible photoluminescence (PL) has been observed from rare earth (Tm, Sm and Dy)-doped AlN films grown by radio-frequency magnetron reactive sputtering. X-ray diffraction indicates that the films are c-axis- oriented hexagonal wurtzite type structure with an average crystal size of about 80 - 110 nm. Room-temperature PL spectra indicate that the blue emission is due to the transition of D-1(2) to F-3(4) and (1)G(4) to H-3(6) intra 4f electron of Tm3+, the yellow emissions of AlN: Sm are due to (4)G(5/2) to the H-6(J) (J = 5/2, 7/2, 9/2, 11/2) and the reddish emissions of AlN:Dy correspond to the F-4(9/2) to H-6(J) (J = 15/2, 13/2, 11/2 and 9/2) and F-6(11/2) transitions.