Evolution of dielectric function of Al-doped ZnO thin films with thermal annealing: effect of band gap expansion and free-electron absorption

Abstract

Evolution of dielectric function of Al-doped ZnO (AZO) thin films with annealing temperature is observed. It is shown that the evolution is due to the changes in both the band gap and the free-electron absorption as a result of the change of free-electron concentration of the AZO thin films. The change of the electron concentration could be attributed to the activation of Al dopant and the creation/annihilation of the donor-like defects like oxygen vacancy in the thin films caused by annealing.

Optical reflectance of solution processed quasi-superlattice ZnO and Al-doped ZnO (AZO) channel materials

“…In order to improve its electrical properties and reduce sheet resistance and resistivity, while also maintaining a lowcost, nontoxic and stable material, ZnO can be doped with trivalent elec tron donor metals such as Al or Ga to ensure high freecarrier mobility and transparency via the Burnstein-Moss shift that gives metal oxides their useful attributes [25]. Modulating the carrier concentration of a material will also affect its optical properties, specifically the plasma frequency, dielectric con stant or refractive index [26]. Introducing a dopant such as Al into the crystal lattice can also produce tensile stress in the crystal lattice.…”

Enhanced X-ray Sensitivity of MAPbBr3 Detector by Tailoring the Interface-States Density

“…29,30 In addition, the indium-free, cost-effective aluminum zinc oxide (AZO) anode has been proved to be an alternative electrode in MAPbBr 3 devices. AZO is an n-type semiconductor 31 with high electrical conductivity. 32,33 The adhesion between a magnetron-sputtered AZO film and the MAPbBr 3 PSC is relatively high, which is easy to standardize and scale up in comparison to C 60 , or BCP.…”

Optical Properties of Al-Doped ZnO Films in the Infrared Region and Their Absorption Applications

“…The obvious crystal peak is (100) in the sample with 450 cycles, which represents the hexagonal wurtzite phase of polycrystalline ZnO [ 30 , 31 ]. Thermal annealing does have an effect on the crystalline property, and this has been discussed elsewhere [ 7 , 9 , 10 , 22 , 32 ]. The thickness-dependent crystallinity can be used to explain the SE results.…”

“…Compared with noble metals, heavily doped semiconductors, such as aluminum-doped zinc oxide (AZO) [ 7 ] and titanium nitride (TiN) [ 8 ], have recently played a more important part in plasmonics and metamaterial applications because of their tunable free carrier concentrations. The doping density [ 8 ], growth atmosphere, and the growth or annealing temperature [ 9 ] were the usual methods to adjust the properties of heavily doped semiconductors. As a heavily doped semiconductor with broad band gap, AZO is a tunable, low-loss plasmonic material capable of supporting high dopant concentrations, and it plays an important role in plasmonic structures [ 10 ].…”