Revealing trap depth distributions in persistent phosphors

Persistent luminescence or afterglow is caused by a gradual release of charge carriers from trapping centers. The energy needed to release these charge carriers is determined by the trap depths. Knowledge of these trap depths is therefore crucial in the understanding of the persistent luminescence mechanism. Unfortunately, the trap depths in...

Thermoluminescence investigation of donor (Ce3+, Pr3+, Tb3+) acceptor (Eu3+, Yb3+) pairs in Y3Al5O12

The thermoluminescence properties of Y3Al5O12 (YAG) doped with an electron donor lanthanide (Ce3+, Pr3+, or Tb3+) together with an electron acceptor lanthanide (Yb3+ or Eu3+) were studied with the aim to locate the energy levels of each divalent and each trivalent lanthanide within the band gap. The activation energies needed to liberate...

Carrier recombination processes and divalent lanthanide spectroscopy in YPO4:Ce3+;L3+ (L=Sm,Dy,Tm)

We studied charge carrier trapping, detrapping, and recombination phenomena in Ce3+ doped YPO4, codoped with Sm3+, Dy3+, or Tm3+. Ce ions trap the holes and Sm, Dy, and Tm trap electrons created during x-ray irradiation. By means of red to infrared stimulation, the trapped electrons can be back transferred to Ce leading to shorter wavelength Ce3...

Controlled electron and hole trapping in YPO4:Ce3+,Ln3+ and LuPO4:Ce3+,Ln3+ (Ln=Sm, Dy, Ho, Er, Tm)

A detailed and systematic electron trapping study was conducted in the scientifically important wide band-gap materials LuPO4 and YPO4 doubly doped with Ce3+ and Ln3+ (Ln=Sm, Dy, Ho, Er, Tm). By using vacuum-ultraviolet luminescence spectroscopy and detailed thermoluminescence spectroscopy it was possible to establish by two independent methods...

Optically stimulated luminescence signals under various stimulation modes assuming first-order kinetics

We present mathematical descriptions of optically stimulated luminescence (OSL) signals under linearly, hyperbolically, exponentially, and reciprocally increasing stimulation intensity for a one-trap one-recombination-center model assuming charge transfer governed by first-order kinetics. Depending on the stimulation mode, the OSL signal can be...

Structures and thermoelectric properties of the infinitely adaptive series (Bi2)m(Bi2Te3)n

Ferromagnetism below 10 K in Mn-doped BiTe

Ferromagnetism is observed below 10 K in [Bi0.75Te0.125Mn0.125]Te. This material has the BiTe structure, which is made from the stacking of two Te-Bi-Te-Bi-Te blocks and one Bi-Bi block per unit cell. Crystal structure analysis shows that Mn is localized in the Bi2 blocks, and is accompanied by an equal amount of TeBi antisite occupancy in the...

Crystal structure and elementary properties of NaxCoO2 ( x=0.32 , 0.51, 0.6, 0.75, and 0.92) in the three-layer NaCoO2 family

Molecular dynamics simulation of interface dynamics during the fcc-bcc transformation of a martensitic nature