Photoluminescence of Er-doped ZnO nanoparticle films via direct and indirect excitation

Abstract

Photoluminescence (PL) of Er-doped ZnO nanoparticle films was studied. The films were grown on silicon ð100Þ or fused silica substrates using e-beam evaporation and subsequently annealed at 700°C in air for an hour. PL was measured at two excitation wavelengths, 325 and 514.5 nm. The 325 nm was used for exciting the host semiconductor ZnO while 514.5 nm was used for directly exciting Er 3þ ions in the ZnO host. Er 3þ luminescence was observed from annealed films using either indirect (325 nm) or direct (514.5 nm) excitations. It has been found that the indirect excitation is significantly more efficient than the direct excitation in producing 1.54 μm photoluminescence. With indirect excitation, the Er 3þ luminescence observed is attributed to energy transfer from ZnO host to the Er 3þ ions doped. Energy transfer from e-h pairs resulting from ZnO host excitation may provide efficient routes for exciting Er 3þ ions inside nano-crystalline particles of the films.

Temperature Effects in the Photoluminescence of Semiconductor Quantum Dots

“…The obtained results show that the multistage relaxation of excited states at indirect excitation causes the complex character of the PL temperature dependence for QDs. So, one can ignore the participation of the highly excited states of the confined exciton and consider the two relaxation stages for the analysis of the mechanism of indirect excitation of Si QDs in the SiO 2 matrix [6].…”

“…According to the results of many studies [4][5][6][7][8][9][10][11][12][13][14], the temperature dependences of photoluminescence in dielectric and semiconductor nanostructures can significantly differ in shape and type when using various excitation methods. The PL temperature curves of quantum dots are most often presented in the form of decreasing functions with increasing temperature [4,5,7].…”

“…This is most often characteristic of direct luminescence excitation of confined excitons [9][10][11][12][13]. The energy transfer of emitting nanoparticles through intermediate electronic states of the matrix [4][5][6][7] can also lead to an increase in PL intensity and to curves with an extreme shape. Thus, there is a need for a detailed analysis of various energy transfer schemes and types of electronic transitions in order to explain the observed variety of forms of temperature dependences of QD photoluminescence [4][5][6][7][8][9][10][11][12][13].…”

Effect of Er doping on microstructure and optical properties of ZnO thin films prepared by sol–gel method

“…The V O is largely present in ZnO due to its low formation energy [11]. A great deal of studies on the photoluminescence (PL) of ZnO show that the green emission is originated from V O which could be significantly affected by dopant incorporation [12][13][14][15], post-annealing [16], prepared conditions [17], and so on. For example, Wang et al [18] found that Al doping could change the concentration of V O in the ZnO thin films, which reflected by the green emission of photoluminescence.…”

Tin Dioxide Nanocrystals as an Effective Sensitizer for Erbium Ions in Er-Doped SnO2Systems for Photonic Applications

“…The energy transfer from semiconductor nanocrystals to Er 3+ ions can efficiently compensate the small cross-section of rare earth transitions. Numerous works have reported the photoluminescent properties of Er 3+ ions in different semiconductors host via indirect or direct excitation [1][2][3][4][5][6][7][8].…”