The effect of postdeposition annealing on the structural and optoelectronic properties of copper bismuth selenide thin films by PVD

Enhanced Photoinduced Carrier Generation Efficiency through Surface Band Bending in Topological Insulator Bi2Se3 Thin Films by the Oxidized Layer

“…However, after 24 h, the absorbance decreased by more than 0.07. Previous studies have reported that the crystallinity degradation significantly decreases absorption. ,,− This clearly demonstrates the contribution of crystallite size and dislocation density toward altering optical absorption. Therefore, a decrease in absorption reduces the number of photocarriers generated by photons, which reduces the intensity of the photocurrent.…”

“…Moreover, electron–hole separation is affected by the built-in potential at the interface between the oxide layer and Bi 2 Se because the difference in the work function induces a built-in potential. , As the results for the maximum band bending and the maximum photocurrent occurred at an exposure time of 24 h, the cause of the increment in the photocurrent is related to surface band bending. In the valence band region shown in Figure b, the point at which the kinetic energy is 21.22 eV (binding energy is zero) is the Fermi level, and a peak is observed up to 6 h. As this peak disappears on increasing the exposure time, it could be caused by the Dirac surface state of the TIs. , In the Bi 2 Se 3 capped by the selenium, to prevent oxidation, the peak was maintained until the selenium was removed just before the UPS measurement (Figure S2). This result supports the fact that the fast response of Bi 2 Se 3 exposed for 6 h contributed to the surface state of the TI.…”

“…In the valence band region shown in Figure 3b, the point at which the kinetic energy is 21.22 eV (binding energy is zero) is the Fermi level, and a peak is observed up to 6 h. As this peak disappears on increasing the exposure time, it could be caused by the Dirac surface state of the TIs. 34,35 In the Bi 2 Se 3 capped by the selenium, to prevent oxidation, the peak was maintained until the selenium was removed just before the UPS measurement (Figure S2). This result supports the fact that the fast response of Bi 2 Se 3 exposed for 6 h contributed to the surface state of the TI.…”

Influence of the electrochemical processing parameters on the photocurrent–voltage conversion characteristics of copper bismuth selenide photoactive films

“…This could be explained by the fact that the bandgap energy decreases with increasing grain size, crystallinity, and homogeneous morphology [44,45]. Also, the recorded film thickness for the successively electrodeposited ~6.1 μm is relatively larger than the simultaneously electrodeposited CBSe film ~1.58 μm, which varies inversely with band gap value [46,47]. The same values of band gaps range (1.67-1.99 eV) were reported for copper bismuth selenide (the same material films) deposited by PVD technique and crystalize in the same phase, i.e., polycrystalline triclinic (Cu 1.6 Bi 4.8 Se 8 ) [46,48].…”

S‐scheme W18O49/Mn0.2Cd0.8S Heterojunction for Improved Photocatalytic Hydrogen Evolution

“…Meanwhile, S has two peaks with binding energies of 160.37 and 160.56 eV, corresponding to S 2p 3/2 and S 2p 1/2 , respectively, and the results were consistent with the previously reported literature. [43][44][45][46] The elemental valence states of each element in pure WO were analyzed, as shown in Figures 3e and 3 f. It can be seen that W has two peaks with binding energies of 35.43 and 37.58 eV, which corresponds to W 4f 7/2 and W 4f 5/2 , respectively, indicating that W exists mainly in the form of W 6 + in WO. And O has a peak binding energy of 530.40 eV, which is attributed to the oxygen bond in WÀ OÀ W formed by W and O atoms.…”