Photoconductive properties of ZnO thin films grown by pulsed laser deposition

Structural, optical and photoconductivity characteristics of manganese doped cadmium sulfide nanoparticles synthesized by co-precipitation method

“…With time dark current decreases and eventually it gets stabilized. This decrease in dark-conductivity is ascribed to dominance of the process of chemisorptions of oxygen after initial dominance of the process of field-assisted desorption of oxygen [59,60]. The stabilized dark-current in CdS:Mn (1 mol%) and CdS:Mn (3 mol%) NPs are higher than dark-current found in un-doped CdS NPs.…”

“…On the contrary free charge carriers increases due to desorption of O 2 . In un-doped CdS as well as Mn-doped CdS NPs, dark current is initially high, which may be attributed to field induced desorption of oxygen molecules because the electric field appears to assist the process of desorption of oxygen [59,60]. With time dark current decreases and eventually it gets stabilized.…”

The effect of indium doping on structural, electrical conductivity, photoconductivity and density of states properties of ZnO films

“…The effect of illumination is to neutralize negative charges in the surface states. Holes also can be captured by deep traps at the grain boundaries resulting in an increase of free electron density and then the photoconductivity [40]. The photoconductive response may be described by traps states.…”

The ultraviolet photoconductive detector based on Al-doped ZnO thin film with fast response

“…The trap states may be related to defects such as dopants, or defects localized in lattice discontinuities (dislocations, grain boundaries and interfaces), or oxygen adsorption at the surface, and or the surface damage during the device processing. Furthermore, it is worthy to note that the 90%-10% fall time is much shorter than that have been reported on the MSM photoconductive detectors based on unintentionally doped ZnO thin films [3,4,7,8], and this may be due to the enhancement of tunnelling recombination across the potential barriers generated by surface and defects with Al doping in ZnO, as the similar behavior was observed in the Si-doped Al x Ga 1−x N photoconductive detectors [14]. The reasons related to the temporal response are analyzed hereinbefore, and the deep mechanisms still need to study further.…”

“…Among various types of photodetectors, metal-semiconductor-metal (MSM) structured photoconductive detectors are generally the simplest detectors to fabricate, and also easy to obtain higher gain and photoresponsivity. Recently, several high performance MSM structured photoconductive detectors based on ZnO thin films have been demonstrated [3,4,[7][8][9]. However, these detectors mainly used the unintentionally doped n-type ZnO thin films and exhibited slow photoresponse.…”