Impact of dopant compensation on the electrical properties of silicon for solar cell applications
Fiacre Rougieux (Research School of Engineering )
SOLAR SEMINAR SERIESDATE: 2012-05-24
TIME: 16:00:00 - 17:00:00
LOCATION: Ian Ross Seminar Room
CONTACT: JavaScript must be enabled to display this email address.
ABSTRACT:
The broad aim of my PhD was to contribute to a better understanding of the mechanisms limiting the efficiency of compensated silicon solar cells (containing boron and phosphorus in the bulk). Such dopant compensation is common in solar grade materials, especially in silicon from the metallurgical route, and can potentially lead to a degradation of the materials electronic properties.
We experimentally show that a thermal oxidation can create an n-type layer at the surface of compensated p-type silicon. This n-type layer is further shown to interfere with device performance and material characterization.
A new method to measure the sum of the majority and minority carrier mobility in silicon is introduced. Measurement of the influence of dopant density, injected carriers and temperature on the mobility sum are made and compared to data available in the literature.
Theoretical calculations show a relatively weak influence of the compensating impurities on the mobility. However experimental results suggest a stronger influence of compensating impurities.
The boron-oxygen defect in compensated n-type silicon is then experimentally investigated. It is shown that if not mitigated, the boron-oxygen defect leads to a strong reduction in implied VOC. The defect is also shown to be fundamentally different in compensated n-type silicon compared to p-type silicon.
BIO:
A world expert in silicon compensation and dancing the robot. Fiacre, soon-to-be submitted will talk about his ph.d works.
