XRD patterns of 200-nm-thick (a) and (b) films as a function of the annealing temperature. The insets represent the AFM surface images of the annealed films. The peaks marked by the blank (◻) and filled (◼) squares correspond to fcc and hexagonal phases, respectively.
Optical microscope images of (a) and (b) films illuminated by the nanopulse laser beams and (c) SEM images of (a). Here, and axes represent the -variation of 15 steps (, step ) and -axis is the -variation of 15 steps (, step ). The insets of (c) represent magnified SEM images for special positions: (i) initial region (no spot), (ii) , , (iii) , , and (iv) , . The illuminated optical energy required for burning was evaluated to be approximately 10.0 and 7.7 nJ for the and thin films, respectively.
Energy band diagram for amorphous chalcogenide suggested in this paper. It is sketched on the basis of the modified Mott and VAP models. Here, it is assumed that the additive Ag atom acts as a donorlike trap (uncompensated ion). onefold chalcogen defect (dangling-bond), threefold chalcogen defect, and , gray tails.
3D mesh and the corresponding power-time effect plots for the nanopulse reflection response in [(a) and (c)] and [(b) and (d)] films. Symbols I and II in (a) and (c) represent the amorphous and crystalline regions, respectively. The reflection difference is , where and are the intensities before and after illumination, respectively.
Log-scaled plots of vs pulse duration for relatively low power . Here, represents the sensitivity defined as a pulse duration corresponding to 50% of the maximum and is the threshold pulse duration.
Plots vs for (a) the as-deposited and films and (b) the annealed films. The optical energy gap is obtained from the intercept on the energy axis of the plot and and represent the slopes in the extended region and the Urbach tail region, respectively. Two slopes relate to randomness in the atomic and electronic configurations.
Dependence of sheet resistance on annealing temperature for the 200-nm-thick (●) and (○) films. Films were annealed in a atmosphere for 1 h at (heating rate ) and all points were average values for three time measurements.
The quantities of , , and determined by the -axis intercept and two slopes in Fig. 6.
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