H2S reactive anneal to reduce carbon in nanoparticle-derived thin films
US9887304B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Jan 30, 2015 |
| Grant date | Feb 6, 2018 |
| Priority date | — |
| Expiry date | Jan 30, 2035 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for preparing CIGS absorber layers using CIGS nanoparticles on a substrate comprises one or more annealing steps that involve heating the CIGS nanoparticle film(s) to dry the film and possibly to fuse the CIGS nanoparticles together to form CIGS crystals. Generally, at least the final annealing step will induce particle fusion to form CIGS crystals. Reactive gas annealing has been found to facilitate the growth of larger grains in the resulting CIGS absorber layers and lead to improved photovoltaic performance of those layers. It is suspected that the presence of carbon in CIGS nanoparticle films hinders grain growth and limits the size of crystals which can be obtained in CIGS films upon annealing. It has been discovered that exposing the CIGS nanoparticle films to a reactive atmosphere containing sulfur can decrease the amount of carbon in the film, resulting in the growth of larger CIGS crystals upon annealing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.