Development Of Low Cost Germanium Photovoltaic Cells For Application In TPV Using Spin On Diffusants

At IMEC presently germanium photovoltaic cells are being developed for application in mechanically stacked solar cells. These stand‐alone germanium cells can also be applied in thermophotovoltaic (TPV) systems. Simulations using the spectrum of an Er2O3 selective emitter heated by a butane burner have been performed to find the most optimal cell parameters. This results in a maximum simulated cell efficiency of 21 percent. In the applied cell process, the emitter is realized by using a spin‐on diffusant and it is passivated using amorphous silicon, deposited by PECVD. Germanium photovoltaic cells have been realized with an AM1.5 efficiency of 6.7 percent, which is amongst the best germanium stand‐alone solar cell efficiencies reported in literature.