Unveiling the Role of H2 Plasma for Efficient InP Solar Cells

III-V semiconductors are among the highest performing materials for solar energy conversion devices. Exposing III-V semiconductors to a hydrogen plasma can improve optoelectronic properties and is a critical step in fabricating efficient InP solar cells. However, there is a limited understanding of the changes induced by hydrogen plasma exposure to the surface and in the bulk of III-V semiconductors. Herein, it is demonstrated that a 19.3% efficient p-InP solar cell with a TiO2 electron selective contact layer can be achieved by exposing the InP substrate to hydrogen plasma. Detailed investigations employing ultraviolet photoelectron spectroscopy and capacitance-voltage measurement unveil that the hydrogen plasma exposure on p-InP leads to charge carrier polarity inversion in the near-surface region (charge inversion layer) while simultaneously reducing the carrier concentration (charge-depleted layer) in the bulk. The study provides important insights into the impact of hydrogen plasma exposures on InP which may lead to more efficient optoelectronic devices such as solar cells, photodetectors, light-emitting diodes, and photoelectrochemical cells.

Automated summary

III-V semiconductors are highly efficient materials for solar energy conversion devices. Exposing them to hydrogen plasma can improve their optoelectronic properties, particularly in the fabrication of InP solar cells. However, the changes induced by hydrogen plasma exposure to the surface and in the bulk of III-V semiconductors are not well understood. This study demonstrates that exposing an InP substrate to hydrogen plasma can achieve a 19.3% efficient p-InP solar cell with a TiO2 electron selective contact layer. Detailed investigations reveal that this exposure leads to charge carrier polarity inversion in the near-surface region and reduces carrier concentration in the bulk. These findings provide important insights into the impact of hydrogen plasma exposures on InP and its potential for enhancing optoelectronic devices such as solar cells and photodetectors.