Effects of Li doping on the structural and electrical properties of solution-processed ZnO films for high-performance thin-film transistors

Highly Visible Photoluminescence from Ta-Doped Structures of ZnO Films Grown by HFCVD

“…This effect could be owing to the fact that tantalum atoms create a compression stress inside the lattice of ZnO, and they prevents an increase in these big shapes, as generated by the difference of ionic radii between Zn and Ta, as commented before in the XRD results. In fact, this phenomenon also has been observed when ZnO is doped with tantalum by other techniques [56], or when ZnO is doped with other materials such as aluminum and lithium [35,42]. compression stress inside the lattice of ZnO, and they prevents an increase in these big shapes, as generated by the difference of ionic radii between Zn and Ta, as commented before in the XRD results.…”

“…compression stress inside the lattice of ZnO, and they prevents an increase in these big shapes, as generated by the difference of ionic radii between Zn and Ta, as commented before in the XRD results. In fact, this phenomenon also has been observed when ZnO is doped with tantalum by other techniques [56], or when ZnO is doped with other materials such as aluminum and lithium [35,42]. The synthesis of smaller structures means that somehow, the relation between the surface/volume of the film will increase, and this fact will be reflected in an increment of reactions between the existing species on the surface of structures, and also a possible increment in the adsorption and resorption of the species in these kind of porous films, and moreover, an increment of cations or anions on the surface of the film, as has been reported in other works; in fact, the role of the surface area has been observed to affect various mechanisms such as gas sensors, biological cells, and the effects of fluorescence emission [28,[59][60][61].…”

“…According to the other reviewed reports, when ZnO is doped with tantalum, the crystallite size is modified, but there is no consensus of the increment or decrement in the crystallite size in ZnO:Ta-doped films; this fact seems to be more greatly affected by the technique used to grow the film; even when ZnO is doped with other materials, the crystallite size sometimes increases, while at other times it decreases [38,40,41]. For example, Bang et al reported the effect of lithium doping in ZnO films, they found that the (002) planes of ZnO were reduced as the Li content was increased; this was interpreted as a degradation of the ZnO crystallinity, while an increase in the grain size was observed as the concentration of lithium increased [42]. Also, it has been reported that the presence of metallic zinc is associated with the existence of the core-shell structures, where the metallic zinc is the core and the ZnO nanocrystals are comprise the shell [37].…”

“…Nevertheless, this mobility was reduced as the carrier concentration increased, because this carrier created a high number of collisions between them, besides the increase in the number of grain boundaries, due to a reduction in the crystal size in the shell. There are reports of ZnO with other dopants, in which it has been observed that foreign atoms inside the lattice of ZnO could act as charge trapping sites [33,42], which prevents the mobility of these free chargers. In our case, Ta atoms could be creating a similar effect, and therefore, the mobility in our films decreases with the amount of Ta 2 O 5 in the source pellet.…”

Suppression of Oxygen Vacancy Defects in sALD-ZnO Films Annealed in Different Conditions

“…The applications of ZnO include solar cells, light-emitting diodes (LEDs), gas sensors, and thin-film transistors (TFTs) [ 1 , 2 , 3 , 4 , 5 ]. ZnO film can be prepared by several techniques, such as pulsed laser deposition (PLD), sputtering, chemical vapor deposition (CVD), solution-based methods, atomic layer deposition (ALD), and molecular beam epitaxy (MBE) [ 6 , 7 , 8 , 9 , 10 , 11 ]. Among these techniques, ALD is distinguished for the self-limiting surface reaction between the precursors which is confined to the substrate surface.…”