Research and Analysis

Venture Capital and Cleantech

My research on the cleantech boom and bust cycle among venture capital investors has been published in Energy Policy and at the MIT Energy Initiative.

From our op/ed in the Financial Times:

In 2006, Silicon Valley began to bet big on clean energy technology. Seduced by grand visions of making a fortune while saving the planet, venture capitalists invested a then-record $123m in the first round of fundraising for 16 new companies that year. In 2008, they would sink nearly $1bn in over 100 new companies.

But when these investments began to flop, the cleantech bubble abruptly popped. Since 2009, VCs have barely funded 25 new cleantech companies a year, slowing new investment to a trickle.

What went wrong? And where should cleantech go from here? To answer these questions, we compared the performance of every medical technology, software technology and cleantech company that received its first round of VC funding between 2006 and 2011. We found that betting on cleantech start-ups just did not make sense for VCs, because cleantech could not deliver the outsized returns found in other sectors.

This conclusion is alarming because new technologies are desperately needed to confront climate change. Still, guided by the lessons learnt from the cleantech VC boom and bust, new private and public funding sources may be able to better support revolutionary technologies.

Materials Science Research

Aluminum Nitride (AlN) is an ideal material for growing high-performance ultraviolet (UV) LEDs and lasers which can be used for water disinfection. However, current growth techniques result a material that cannibalizes the UV light it generates. Making these devices practical requires finding (and fixing) the cause of this parasitic absorption.

Schematic of an LED structure and the carbon defect.
The structure of an LED showing the AlN substrate, and an exploded view of a simulation cell that includes a carbon defect.

An international, multidisciplinary collaboration among simulation, synthesis, and characterization teams at the Wide-Bandgaps group at NC State, HexaTech, Tokyo University of Agriculture and Technology, and Tokuyama Corporation allowed us to predict theoretically and then confirm experimentally that a carbon impurity was to blame.

For further details, please see our paper published in Applied Physics Letters. My other doctoral research was published in Physical Review B, Nature Materials, and Nature Communications. A full list can be found on my Google Scholar profile.