InGaN devices for high temperature photovoltaic applications

In this work we present the temperature-dependent photovoltaic behavior of InGaN homojunction structures confirming the feasibility of these materials for use in high temperature photovoltaics. Homojunction p-n and p-i-n structures from materials with In content >30% have been processed into PV test devices and, despite being not optimized, without surface passivation or anti-reflection coating (ARC), demonstrated significant spectral response at energies above 2.0 eV. J-V curves under AM0 or concentrated UV illumination were performed at temperatures from 25°C up to 250°C. Devices exhibited fractional Jsc reduction of ~15% of their room temperature value at 200 °C, and ~20% at 250°C. Although typical Si-and GaAs-based solar cells tend to increase Jsc slightly when heated, the drop for the InGaN devices is a very encouraging result, since their lack of passivation and other optimizations will have an effect on their temperature dependent behavior.