Optical Switching of Quantum Confinement-Tunable Semi-Transparent Solar Cell Based on Ultrathin Germanium

Abstract

In this contribution, we study the effects of optical switching on quantum confinement of a semitransparent solar cell based on an ultrathin amorphous germanium absorber placed inside a resonant nanocavity. The optical switching of the cavity is based on the transition of the back contact from metallic opaque Mg to dielectric semitransparent MgH2 after the absorption of hydrogen. Optical simulations show that the electric field confinement and local absorption inside the device depend strongly on both, the state of the switchable mirror layer and the size-dependent optoelectronic properties of the QW absorber. The quantum confinement tuning enables thickness reduction, while providing enhanced efficiency and promoted transmission in optically switchable semitransparent QW a-Ge:H technology. This work paves the way to the usage a fully switchable photovoltaic window.