Mobility activation in thermally deposited CdSe thin films

Abstract

Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated CdSe thin films deposited on suitably cleaned glass substrate held at elevated substrate temperatures. The study indicates that the mobilities of the carriers of different trap levels are activated due to the energy of incident illumination, which results in the existence of two distinct trap levels. In each trap depth the energy of the trap increases linearly. It infers that there is a linear distribution of traps of different energies below the conduction band.

Structural, optical and charge transport study of rutile TiO2 nanocrystals at two calcination temperatures

“…Kangkan et al have reported that the increase in PC occurs due to two contributors viz. one from the resultant increase in the photogenerated charge carriers and other due to the increase in the effective mobility which is a function of temperature [72]. A high value of electron mobility for sample R2 also implies that the sample R2 is pure and structurally more perfect than sample R1.…”

Effect of Intensity and Wavelength of Illumination on the Photoelectronic Properties of Nanocrystalline CdSe Thin Films

“…From this figure it is observed that there exist 2 different slops in the plots, which indicates the existence of 2 distinct trap levels, E1 and E2, at the considered room temperature. The trap depths are not single valued and there is a quasi-continuous distribution of trap levels below the conduction band [21,34]. It may be noted that photocurrent in these thin films is found to obey a sub-linear relation with the intensity of illumination (Figure 5(a)) which may be explained on the basic of defect controlled photoconductivity mechanism.…”

“…Nanocrystalline thin films of CdSe have been prepared using different methods [9][10][11][12][13][14][15][16], out of which CBD technique is mainly used because of its simplicity, effectiveness and variability [17][18][19]. Although wide range of works on the synthesis and characterization of nanocrystalline thin films of CdSe have already been reported [9][10][11][12][13][14][15][16][17][18][19], but only few works on the photoelectronic properties specifically based on the wavelength and the intensity of incident illumination have been found in the available literatures [20,21]. Reported works have basically considered the complete range of visible light spectrum i.e.…”

Numerical simulations of N-type CdSe poly-TFT electrical characteristics with trap density models of Atlas/Silvaco

“…Many studies of traps in poly-CdSe films [7][8][9][10] have revealed that there are two kinds of bulk trap states relevant for poly-TFTs electrical characteristics. In case of N-type poly-CdSe, they refer as shallow and deep traps with energy densities peaking at around 0.13 eV and 0.4 eV bellow the conduction band, respectively [7][8][9][10].…”

“…In case of N-type poly-CdSe, they refer as shallow and deep traps with energy densities peaking at around 0.13 eV and 0.4 eV bellow the conduction band, respectively [7][8][9][10]. It has been recently shown [10] that the experimentally observed gradual transition from the subtreshold to the postthreshold regime of CdSe poly-TFTs is due to effect of the trapping-detrapping process at shallow trap states, whereas the subtreshold slope has a strong dependence on TDD of the deeper traps.…”