|About this Abstract
||2010 Electronic Materials Conference
||TMS 2010 Electronic Materials Conference
||J3, Quantum Dot n-i-p-i Photovoltaic Devices
||Michael A Slocum, Steven Polly, Chelsea Plourde, Christopher Bailey, Jeremiah McNatt, Sheila Bailey, Cory Cress, David V Forbes, Seth M Hubbard
|On-Site Speaker (Planned)
||Michael A Slocum
State of the art space solar cells utilize epitaxially grown III-V multijunction cells, with champion devices exceeding 30% conversion efficiency under 1-sun AM0 illumination. The ultimate efficiency is limited by the dual constraints of current matching in the series stack and lattice matching within the epitaxial structure to eliminate structural defects. This paper will focus on a novel approach of combining the benefits of an intermediate band solar cell (IBSC) with a device that depends almost exclusively on drift rather than diffusion currents to collect the carriers. A quantum dot nipi (QD-nipi) architecture consisting of repeating n-i-p-i epitaxial layers has been proposed to increase the radiation hardness of a device due to a decreased dependence upon diffusion length. This architecture will allow photo generated carriers to be rapidly converted to majority carriers by drift, and conducted laterally through selective contacts positioned at opposite sides of etched V-groove channels in the device. Enhanced spectral conversion can occur by simultaneously adding QD to the stack. Demonstration of the QD-nipi configuration in a GaAs photovoltaic cell presents several challenges to device design and epitaxial growth. This paper will describe progress in addressing the two main challenges of creating selective ohmic contacts and determining the electric field profile. Results will be presented from epitaxial regrowth of GaAs within etched V-groove channels, concentrating on structural and electrical characteristics.