Preparation And Analysis Of Thin Films For Solar Energy

The crisis of exhaustion of fossil energy has motivated various seeking for alternative energy sources, which has cost tremendous labor and economic efforts. The study of utilization of solar energy, one of non-exhaustible and non-polluting energy sources, has great significance in the sustainable development of human society and drawn increasing interests from scientific researchers.The study of amorphous silicon is one of the core issues among the researches on amorphous semiconductor materials and devices. The a-Si:H film is one of typical killer-applications of amorphous silicon devices. Its unique physical characteristic and brilliant processability enables its usage as highly efficient photoelectric conversion material in broad solar cells and LCD monitor panels. Compared with its monocrystalline silicon counterpart, a-Si:H-based solar cell has a promising potential in terms of better conversion rate, lower manufacture cost and mass production.AlN is a insulation material of III-V compound, which is a hexagonal wurtzite crystal structure and has wide bandgap energy band. Its energygap is 6.2eV at nomal temperature. AlN atoms combine with covalent bonding. It has high melting point, good chemical stability and high thermal conductivity, while its thermal expansion coefficient is similar to silicon, and also has a low dielectric constant, dielectric loss and other properties. These characteristics made it have infinite potential in the fields of electronic substrates, semiconductor encapsulation, heat dissipation of electronic components and so on. As it have excellent piezoelectric characteristic and high velocity of surface acoustic wave(SAW), AlN has become the best materials that develop the subassembly high-frequency acoustic wave. Because of a wide band gap, the same lattice structure with GaN and less lattice mismatch, AlN can be used as the insulating layer, protective layer or buffer layer of semiconductor technology. All things show AlN has a extensive prospect of applicationAmorphous silicon films have been successfully synthesized on flexible substrate by HWCVD.The growth rate, surface morphology, and the microstructures of the films were studied using Taylor step tester, AFM, and XRD respectively. The results showed that increase of the silane concentration and the substrate temperature resulted in increases of the growth rate and the particle size of the films, and that also made the film surface more uniform. The crystallinity of the deposited films was enhanced by decreases of silane concentration or increases of the substrate temperature. The growth rate, film morphology, and microstructure are not sensitive to the deposition pressure. Al (W)-AlN selective absorption thin films have been successfully synthesized using magnetron sputtering technique under a mixed gas of high-purity nitrogen and argon. The optical absorption characteristics of single-layer or the multi-layer AlN thin films on the W and Al reflecting layer were compared through the analysis of the absorption spectra. The results indicated that the absorbency of the multi-layer AlN thin films is better than that of the single-layer, and W layer was more suitable to be used as reflecting material than Al layer. The absorptivity of the gradual change multi-layer AlN thin film on the W reflecting layer at full-wave band of solar spectra can be over 80%.