Undoped tin oxide (SnO2) thin films have been deposited in a stagnant point flow chemical vapor deposition reactor. By adding methanol during the deposition process ten times more conductive SnO2 films are obtained, with remarkably high mobility values of up to 55 cm2/Vs. The investigations on the morphological and structural properties indicate that the main effect of methanol is the densification of the SnO2 films, which probably causes the improvement in the electrical properties. In all conditions the nucleation and coalescence phases take place very early in the growth. The films are already very conductive at a thickness below 10 nm, which is very beneficial to applications that have strict requirements in terms of film transparency. This high conductivity was attributed to a high carrier concentration, obtained without intentional doping.

This paper reports a plasma-assisted, rapid, ambient-pressure, low-temperature one-step process for depositing conformal, non-porous nanocrystalline ZnO thin film on various substrates ranging from Si (100), fused quartz, glass, muscovite, c- and a-plane sapphire (Al2O3), to the common polymer polyimide (KaptonTM). The as-synthesized polycrystalline films range in thickness from 20nm to 200nm, deposited at a growth rate ranging from 2 nm/min to 50 nm/min. The lowest deposition temperature achieved with this method is 180°C and progress is being made in further lowering this temperature. The as-deposited films are highly oriented in the caxis, with (002) being the dominant planes.

This paper reviews the status of hollow cathode sputtering as an evolving technology for production of thin-film transparent conducting oxides for PV applications. A large market segment for PV TCOs is represented by thin-film a-Si:H and tandem a-Si:H/nc-Si:H modules. For superstrate devices, textured SnO2:F produced on-line by APCVD is currently the market leader, although alternative off-line methods and materials are now emerging. In particular, zinc oxide can be produced by LPCVD, APCVD, magnetron sputtering, and hollow cathode sputtering (HCS). HCS is a stable process featuring low-cost metal targets and a soft deposition process. We discuss the deposition principles and the film results obtained using linear hollow cathodes 0.5 m and 1.0 m in length. We report the direct deposition of highly textured doped ZnO having an electron mobility in excess of 50 cm2/Vs. The production cost of textured ZnO is estimated for several competing techniques.

For successful implementation of the nanomaterial-based PV and Energy storage devices there is a need for well-structured nano films consisting of a strictly controlled sequence of nanoparticle layers. Most promising nano-films include a “built-in” gradient of a nanoparticle size and/or material composition across the part or entire thickness of the film. Such Gradient Multilayer (GML) nano films will be able to significantly improve a PV efficiency of the 3rd generation Solar Cells and Energy storage devices. The development of GML-based devices is presently limited by lack of simple, inexpensive, scalable, and production-worthy deposition methods that are capable of forming GML nano-film on PV-suitable substrates such as flexible materials.

The proposed concept describes novel principles of an advanced non-conventional deposition of the highly efficient GML nano films.

The proposed GML deposition method is based on the phenomena of Flying Particles (FP). According to the FP-methods a pre-selected mix of nanoparticles (NP) of various size and/or material composition is deposited on a flexible (or other) substrate in a pre-defined order of NP size and/or composition thus forming GML nano film. Deposited GML film comprises a sequence of size-tuned and/or composition-tuned NP layers, which has a potential for significant increase of PV efficiency.

The deposition process includes the NPs launch and flight through a resistant gas ambient. Due to the Stokes aerodynamic laws the FP times-to-target will be different for NP of a different size and/or density (material composition). Simulation is presented to confirm the separation of FP”s of a different size and/or density during their motion through the low-pressure gas. The calculations have been made for the initial stages of the FP process thus establishing the most efficient parameters of the process. Resultant GML nano films are expected to have superior qualities, particularly for building high efficiency / low cost PV panels. The FP-method allows for a fast development and easy implementation in PV manufacturing.

Aluminum doped ZnOx (ZnOx:Al) films have been deposited on glass in an in-line industrialtype reactor by a metalorganic chemical vapor deposition process at atmospheric pressure. ZnOx:Al films can be grown at very high deposition rates of ~ 14 nm/s for a substrate speed from 150 mm/min to 500 mm/min. ZnOx:Al films are highly conductive (R < 9 Ohm/sq, for a film thickness above 1300 nm) and transparent in the visible range (> 80%). Amorphous silicon p-i-n solar cells have been grown on as deposited ZnOx:Al films, without optimizing the surface texturing of ZnOx:Al films to enhance light scattering. An initial efficiency of approximately 8% has been achieved.

In this study electron backscatter diffraction (EBSD) investigation is carried out for CuIn1-xGaXS2 (CIGS2) samples that were prepared by two stage process in which the initial precursor was deposited by DC magnetron sputtering followed by sulfurization in conventional furnace. Due to high surface roughness, low quality EBSD signal was obtained in the samples that were initially polished with ion milling. Polishing with dimpler grinder followed by chemical treatment with bromine/methanol solution improved the quality of EBSD patterns. Efforts are being made to build the database for CIGS2 in the system using high quality EBSD patterns and finally to obtain grain orientation maps.