Department of Physics and Astronomy

PhD Public Lecture

Ali Hatef

Supervisor: Dr. Mahi Singh

“Quantum Coherence and Interference in Metallic Photonic Crystals and Hybrid Systems”

DATE:            FRIDAY, 9^th December 2011

TIME:             1:00 p.m.

PLACE:         Physics & Astronomy Room 22

All are welcome to attend.

Poster: http://www.physics.uwo.ca/colloquia/Colloquia%20Notices/2011_2012/KHERANI%20Colloquium.pdf

PHYSICS & ASTRONOMY COLLOQUIUM

Date:           Thursday, 8^th December 2011
Time:          1:30 p.m.
Location:    Physics & Astronomy Seminar Room 22

Dr. Nazir P. Kherani
Electrical and Computer Engineering
University of Toronto

“Photovoltaic –Photonic Crystal Interplay”

ABSTRACT

On the steps of Volta’s discovery of the voltaic effect in 1800 and Becquerel’s discovery of the photovoltaic effect in 1839, followed more than a 100 years of research before scientists at Bell Laboratories developed the first silicon pn junction photovoltaic device. In the intervening 60 years great strides have been made in the field of photovoltaics (PV). Today it is recognized that PV can become a significant component of sustainable terrestrial energy sources. It is non‐polluting, environment friendly, and its fuel is distributed relatively uniformly and is free.

However, with the continual drive towards grid‐parity and thus reduction of cost per peak watt, a range of novel approaches are being pursued which offer the potential combination of reduction in material and processing costs and maximal solar utilization. In this context, photonic crystals present interesting light propagation control that could make them amenable to novel photovoltaic‐photonic crystal integrations. Recently, we have proposed a novel class of photonic crystals, called selectively transparent and conducting photonic crystals (STCPCs). These STCPCs, a significant advance over existing 1D PCs, combine intense wavelength selective broadband reflectance with the transmissive and electrically conductive properties of sputtered transparent conducting oxides. This integration of optical and electrical functionalities into a single device element has opened the way for performance enhancement in a range of optoelectronic devices including photovoltaics.

The talk will provide an overview of photovoltaics, highlighting a range of device material systems and cell concepts and their associated strengths and challenges. The presentation will then focus on our recent studies on the potential use of photonic crystals in PV devices, with an emphasis on their application in thin film silicon solar cells; specifically, their application of selectively transparent and conducting photonic crystals in photovoltaics and allied devices will be underlined. Allied investigations into low‐cost high‐efficiency ultra‐thin silicon photovoltaics and recent laser-assisted synthesis of tailorable light trapping patterns in silicon will also be presented.

Coffee & cookies will be available, courtesy of