We report on the application of a static (dc) electric field in the plume region during the pulsed Nd doped yttrium aluminum garnet laser deposition (PLD) of tetrahedral amorphous carbon (ta-C) films in vacuum ambient $(\text{pressure}={10}^{-4}–{10}^{-3}\mathrm{Pa})$ , where the working pressure is exclusively due to ablation vapor. This approach is strikingly different from the plasma- or ion-beam-assisted PLD because the mean free path at this pressure is by far longer than the target to substrate distance. Thus, the electric field interacts with individual ionized species invoking ion acceleration and gas-phase reactions among different ionized species. These phenomena are clearly dependent on the laser wavelength (first, second, or third harmonic, $\lambda =1064$ , 532, and $355\mathrm{nm}$ , respectively) used for the ablation. We found that the application of the electric field causes surface smoothing (the roughness decreases from about $1\text{to}0.4\mathrm{nm}$ ) and faster deposition rate (from about $2\text{to}7\mathrm{nm}∕\min$ ) for the second and third harmonics. In addition, the phenomena are less intense in the case of the first harmonic due to the low concentration of ionized species in the plume. In addition, in the case of PLD using $\lambda =532\mathrm{nm}$ , the electric field improves the film’s density (from $2.60\text{to}2.95\mathrm{g}∕{\mathrm{cm}}^3$ ). The correlations found are discussed in terms of the ablated species and the deposition mechanisms of the ta-C.

Resistivity and transparency of zinc-oxide layers (ZnO) for chalcopyrite photovoltaic technology applications were engineered by activation of the Burstein–Moss (BM) effect at high concentrations of aluminium (Al) and indium (In) dopant. The Al:ZnO and In:ZnO layers were processed by cost-effective, large-area, fast-rate electrochemical deposition techniques from aqueous solution of zinc nitrate (Zn(NO₃)₂) and dopant trichlorides, at negative electrochemical potential of E_C = (−0.8)–(−1.2) V, moderate temperature of 80 °C, and solute dopant concentrations of AlCl₃ and InCl₃ up to 20 and 15 mM, respectively. Both Al:ZnO and In:ZnO layers were deposited on Mo/glass substrates with ZnO and ZnO/ZnSe buffers (Al:ZnO/ZnO/Mo/glass, In:ZnO/ZnO/ZnSe/Mo/glass), respectively. Based on the band-gap energy broadening of Al:ZnO and In:ZnO originated by the BM effect, maximum carrier concentrations of the order 10²⁰ and 10²¹ cm⁻³, respectively, were determined by optical characterization techniques. The (electrical) resistivity values of Al:ZnO calculated from optical measurements were commensurate with the results of electrical measurements (10⁻⁴ Ohm·cm). In both cases (Al:ZnO and In:ZnO), calibration of carrier density in dependence of solute dopant concentration (AlCl₃ and InCl₃) was accomplished. The p–n junctions of Au/In:ZnO/ZnO/ZnSe/CIGS/Mo on glass substrate exhibited current–voltage (I–V) characteristics competing with those of crystalline silicon (c-Si) solar cells.

High quality polycrystalline bilayers of aluminium doped ZnO (Al:ZnO) were successively electrodeposited in the form of columnar structures preferentially oriented along the $\left(10\overline{1}1\right)$ crystallographic direction from aqueous solution of zinc nitrate (Zn(NO₃)₂) at negative electrochemical potential of E_C = (−0.8)–(−1.2) V and moderate temperature of 80 °C on gallium rich (30% Ga) chalcopyrite selenide Cu(In,Ga)Se₂ (CIGS) with chemically deposited ZnSe buffer (ZnSe/Cu(In,Ga)Se₂/Mo/glass). The aluminium doped ZnO layer properties have initially been probed by deposition of Al:ZnO/i-ZnO bilayers directly on Mo/glass substrates. The band-gap energy of the Al:ZnO/i-ZnO reference layers was found to vary from 3.2 to 3.7 eV by varying the AlCl₃ solute dopant concentration from 1 to 20 mM. The electrical resistivity of indium-pellet contacted highly doped Al:ZnO sheet of In/Al:ZnO/i-ZnO/Mo/glass reference samples was of the order ρ ~10⁻⁵ Ω·cm; the respective carrier concentration of the order 10²² cm⁻³ is commensurate with that of sputtered Al:ZnO layers. For crystal quality optimization of the bilayers by maintenance of the volatile selenium content of the chalcopyrite, they were subjected to 2-step annealing under successive temperature raise and N₂ flux regulation. The hydrostatic compressive strain due to Al³⁺ incorporation in the ZnO lattice of bilayers processed successively with 5 and 12 mM AlCl₃ dopant was ε_h = −0.046 and the respective stress σ_h = −20 GPa. The surface reflectivity of maximum 5% over the scanned region of 180–900 nm and the (optical) band gap of E_g = 3.67 eV were indicative of the high optical quality of the electrochemically deposited (ECD) Al:ZnO bilayers.

In this paper the internal electric fields of nearly lattice matched InAlN/GaN heterostructures were determined. Pin -diodes containing InAlN/GaN heterostructures grown on sapphire substrates by metalorganic vapour phase epitaxy were fabricated by standard lithography and metallization techniques. To determine the polarization fields in the InAlN quantum wells capacitance-voltage-measurements were performed on the pin -diodes. To reduce the measurement error, the heterostructure thicknesses were accurately determined by transmission electron microscopy. Large polarization fields, which correspond mainly to the spontaneous polarizations, for In _0.15 Al _0.85 N ( MV cm ⁻¹ ), In _0.18 Al _0.82 N ( MV cm ⁻¹ ) and In _0.21 Al _0.79 N ( MV cm ⁻¹ ) quantum wells were observed. The results of the internal field strength and field direction are in excellent agreement with values predicted by theory and a CVM-based coupled Poisson/carrier transport simulation approach.

ZnSe thin films were processed in-vacuum by EBD and in-solution by CBD for comparative studies of CdS-buffer replacement of ZnO/CdS/Cu(In,Ga)Se₂/Mo/glass solar-cells. ZnSe films deposited by EBD, at e-beam energies 11keV, on polycrystalline CuGaSe₂, at 400°C, were microcrystalline, with average grain-sizes 100nm, and (111)zinc-blende(ZB)-structure. The films exhibited compressive mismatch-stresses σ = −0.9 GPa. The absorption coefficient α = 6.2 × 10³cm⁻¹ and the energy band-gap E_g = 2.69eV indicated optical transparency suitable for buffer/solar-absorber configurations. In CBD, zinc-sulfate_(ZnSO₄) solution with selenourea_(SeC(NH₂)₂), ammonia_(NH₃), hydrazine_(NH₂NH₂), and sodium-sulfite_(Na₂SO₃) were processed at solution-bath temperature 70°C. The growth-rates of ZnSe on glass_(1.2nm/min), epitaxial_CuGaSe₂/GaAs(001)_(7.4nm/min), and polycrystalline_Cu(In,Ga)Se₂/Mo/glass_(17.6nm/min) were strongly facilitated by substrate order, orientation, and conductivity. Mismatch-stresses switched from compressive σ = −0.5GPa of ZnSe_on_epitaxial_CuGaSe₂/GaAs(001) to tensile σ = 1.1-1.9GPa of ZnSe_on_polycrystalline_Cu(In,Ga)Se₂/Mo/glass. Film crystallinity was improved by post-growth annealing (300°C,2h,Ar/N₂). The energy band-gap E_g = 2.73-2.87eV was broadened with the increase of annealing-time. ZnSe films were deposited by CBD on polycrystalline Cu(In,Ga)Se₂ with (101)wurtzite(WZ)-structure. Following process-optimization, high quality ultra-thin films with (ZB)-structure were produced. The quality assessment of ZnSe films processed by cost-effective, easy-applicable, fast-rate, large-area, moderate-temperature CBD competes with that of EBD processed films and opens the perspective for strain-free CIGS TFSCs by lattice-matching of ZB/WZ-ZnSe bilayer to chalcopyrite sub-layer and ZnO over-layer.