Effect of residual gas on the optoelectronic properties of Mg-doped Ga0.75Al0.25N (0 0 0 1) surface

Comparison Study of Structural Stability and Optoelectronic Properties of Al0.5Ga0.5N Thin Film and Nanowire Photocathode Surfaces under Different Activation Methods

“…While the Al 0.5 Ga 0.5 N supercell is built by substituting 50% Ga atoms for Al atoms based on GaN until the cell with wurtzite structure, whose space group is P6 3 mc, symmetry is C 6v-4 , and lattice constants of a = b = 3.189 Å, c = 5.185 Å, and α = β = 90°and γ = 120°. 21,21 The opposing six Al−Ga−N atomic layers use H passivation at the bottom to eliminate the effects of bottomdangling bonds. 21,22 For the pure Al 0.5 Ga 0.5 N thin film model, there are 52 atoms, containing 12 Al atoms, 12 Ga atoms, 24 N atoms, and 4 H atoms.…”

“…21,21 The opposing six Al−Ga−N atomic layers use H passivation at the bottom to eliminate the effects of bottomdangling bonds. 21,22 For the pure Al 0.5 Ga 0.5 N thin film model, there are 52 atoms, containing 12 Al atoms, 12 Ga atoms, 24 N atoms, and 4 H atoms. The Al 0.5 Ga 0.5 N thin film surface model has three double layers with relaxation on top and fixed positions of three double layers below to simulate bulk conditions.…”

“…The surface model of pure Al 0.5 Ga 0.5 N thin film is obtained through a 2 × 2 × 3 Al 0.5 Ga 0.5 N supercell. While the Al 0.5 Ga 0.5 N supercell is built by substituting 50% Ga atoms for Al atoms based on GaN until the cell with wurtzite structure, whose space group is P 6 3 mc , symmetry is C 6 v ‑4 , and lattice constants of a = b = 3.189 Å, c = 5.185 Å, and α = β = 90° and γ = 120°. , The opposing six Al–Ga–N atomic layers use H passivation at the bottom to eliminate the effects of bottom-dangling bonds. , For the pure Al 0.5 Ga 0.5 N thin film model, there are 52 atoms, containing 12 Al atoms, 12 Ga atoms, 24 N atoms, and 4 H atoms. The Al 0.5 Ga 0.5 N thin film surface model has three double layers with relaxation on top and fixed positions of three double layers below to simulate bulk conditions.…”

Exploration on structural stability, electronic and optical properties of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin film and nanowire photocathode surface

“…Due to the stability and conductivity of the second surface are better than the first surface [18][19][20], we mainly discuss the activation of AlGaN thin films surface when Ga and Al atoms are the outermost. The pure surface model of Al 0.5 Ga 0.5 N thin films consists of six Al-Ga-N atomic layers, which contain 32 N atoms, 16 Ga atoms and 16 Al atoms, and H passivation is used at the bottom to eliminate influence of bottom suspension bond [21,22], as shown in figure 1(a). To simulate the bulk condition, during the structure optimization process of Al 0.5 Ga 0.5 N thin film surface model, the upper three double layers are relaxed and the lower three double layers are fixed in geometric position.…”

“…Finally, we have used the DFT-D3 of Tkatchenko and Scheffler method to calculate the energy of activated Al 0.5 Ga 0.5 N surface models. The generation of dipole moment results in activated AlGaN having a lower work function and dipole correction is not included in our calculations [14,21,24].…”