In the present paper, we discuss the influence of point defects on electrical and
optical characteristics of ZnO thin films grown by the atomic layer deposition (ALD)
method on glass and silicon substrates at low temperature (100°C). Room temperatu
re
photoluminescence (RT PL) spectra, secondary ion mass spectroscopy (SIMS), and Hall
Effect measurements were made for as-grown ZnO layers. The annealing process was
performed in air as well as in N2 atmosphere at 400°C for half an hour. The long annealing
resulted in a larger reduction in electron concentration. Simultaneously, an evident
increase in carrier's mobility was observed, which may suggest that annealing resulted in a
decreased number of native defects in the ZnO layers. Also, it was observed that hydrogen
atoms in ZnO samples did not dominate their electrical properties with the increase of
electrons concentration.
Monodispersed CdSe Nanorods nanoprticles with sufficient luminescence intensity have been prepared by chemical method in solution phase. CdSe as a core covered by Olic acide as an organic capping agent. The nanodots size obtained by two methods: dir
ectly from high resolution transmission electron microscopy (TEM) and using absorption peaks comparison with literature, the two methods are in good agreement. The optical properties and the luminescence intensity as a function of CdSe NRs concentration and the type of solvent (Chloroform and Toluene) have been investigated. The intensity of photoluminescence peak decreases and the peak shifts toward the blue energy side as the concentration reduced. The results show the relation between the polarity, the effect of surface, concentration, and the quantum effect on the optical properties.
Monodispersed CdSe nanoparticles with sufficient luminescence intensity have been prepared by chemical method in solution phase, and in two forms: CdSe as a core covered by Olic acide as an organic capping agent, while the second form is CdSe as a co
re covered by a layer of CdS (CdSe/CdS core shell). The nanodots size obtained directly from high resolution transmission electron microscopy (TEM) and absorption peaks using Paul Mulvaneys formula are in good agreement. The optical properties and the luminescence intensity as a function of CdSe concentration and the type of solvent have been investigated. The intensity of photoluminescence peak decreases and the peak shifts toward the blue energy side as the concentration reduced
