Bifacial Schottky-Junction Plasmonic-Based Solar Cell

Abstract

Plasmonically-enhanced and Schottky-based devices are very appealing candidates for sunlight energy–harvesting applications. However, this class of structures introduces inherent limitations such as thermionic emission (and the related dark current). This article theoretically proposes using the metal–semiconductor–metal heterojunction under bifacial mode. In this design, plasmonic periodic gratings are introduced in the bifacial configuration to allow collection of light from both faces of the solar junction. This results in improved carrier generation and enhanced device performance of a cell with a 3 μm thick Si absorber. Bifacial gain for short circuit current is found to be 88%, with a bifaciality factor (the ratio of rear to front response of the device) of 84%. By optimizing the filling fractions of the front and rear plasmonic gratings, the obtained normalized output becomes higher than 25%; i.e., it almost doubles the performance in comparison with the monofacial Schottky solar cell.