Download Project tiphy020b abstract

ICHEC Class B Application:
The Amorphous-Crystalline Si Interface and its Influence on Photovoltaic Properties.
PI:
Dr. Giorgos Fagas, Tyndall National Institute, Prospect Row, Lee Maltings, Cork
Co-workers:
Mr. Merid Legesse, PhD student, Tyndall National Institute, Prospect Row, Lee Maltings, Cork
Dr. Michael Nolan, Tyndall National Institute, Prospect Row, Lee Maltings, Cork
1. Abstract
The project “The Amorphous-Crystalline Si Interface and its Influence on Photovoltaic
Properties” will undertake first principles density functional theory (DFT) simulations of the
technologically important interface between amorphous and crystalline silicon (aSi-cSi) in model
extended planar structures. These structures are of great interest as leading candidates for next
generation silicon photovoltaics (PV), whereby the light absorption and charge transport
properties can be engineered by composition and structure to tune their response to incident
light. The project will apply a heat and quench simulation approach, in which crystalline Si
surfaces of different orientation are heated to high enough temperature to induce partial melting
for different times and then quenched to 0 K to produce a region of amorphous silicon interfaced
with crystalline Si, i.e. an aSi-cSi heterostructures. The structures resulting from this can produce
different thickness aSi, depending on the initial melting time and the crystal face and these will
be relaxed with DFT. Addition of hydrogen passivates the aSi region. The electronic and optical
properties of the aSi-cSi heterostructures will be determined, in particular the valence and
conduction band offsets will be studied, along with the open circuit voltage, Voc. The results of
these studies will be used in collaboration with experiment to allow a deep understanding of how
the structure of aSi-cSi heterostructures determines PV properties, which will be crucial for
developing high efficiency next generation PV devices.