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OSE Special Seminar by Dr. Jani Oksanen on Energy and photon transport in thermophotonic devices

Departmental News

Dr. Jani Oksanen seminar image

Posted: November 29, 2017

Where: P&A, Room 190

When: Monday, December 4, 2017  10:00 AM - 11:00 AM 

Abstract: Fundamentally, the possibility of both electroluminescent (EL) and photoluminescent (PL) cooling of semiconductors arises from the thermodynamic principles of light emission. The key difference between the two phenomena, on the other hand, is the mechanism of exciting the semiconductor. These differences and similarities create many common challenges but also lead to several different approaches to solve them.

We study the physics and transport effects primarily related to electroluminescence, aiming to demonstrate and harness this effect in thermophotonic (TPX) heat pumps combining the EL cooling effect with energy recycling provided by photovoltaic cells. Our work focuses both on the experimental realization of TPX devices as well as on developing the models and modeling tools needed to understand the pertinent optical, electrical and thermal transport effects and related interactions.

In this seminar, I will give an overview of our progress and the challenges related with optical cooling, as well as discuss the selected most important physical effects and models needed to understand the phenomena in more detail. This includes topics ranging from fluctuational electrodynamics and charge transport modeling to experimental work involving growth, processing, and characterization of conventional compound semiconductors and devices. In addition, I will also discuss some of our recent results related to the diffusion-driven charge transport, which started out as a possible means to reduce the resistive losses in large area LEDs to the level allowing the realization of large area TPX devices and may also find use e.g. in the electrical injection of nanowires.