Mechanically Exfoliated InP Thin Films for Solar Energy Conversion Devices

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• III-V semiconductors are ideal for solar energy conversion due to their bandgap but are costly.
• Thin-film approaches can mitigate the high cost of III-V semiconductors.
• Developing cost-effective methods for thin-film III-V semiconductor fabrication is crucial for widespread adoption.

Purpose of the Study:

• To demonstrate a novel, cost-effective mechanical exfoliation technique (controlled spalling) for producing thin films of III-V semiconductors.
• To validate the optoelectronic properties of exfoliated indium phosphide (InP) films.
• To fabricate and assess the performance of solar energy conversion devices using these thin films.

Main Methods:

• Mechanical exfoliation (controlled spalling) was employed to obtain 15 μm thick InP films.
• Cathodoluminescence and photoluminescence spectroscopy were used for material characterization.
• InP thin-film heterojunction solar cells and InP photoanodes with NiFeOOH catalyst were fabricated.

Main Results:

• Successful exfoliation of 15 μm thick InP films without compromising optoelectronic properties.
• Fabricated InP thin-film solar cells achieved power conversion efficiencies exceeding 13%.
• Developed InP photoanodes demonstrated a photocurrent density of 19.3 mA cm⁻² at 1.23 V RHE and ≈4% applied bias photon-to-current efficiency.

Conclusions:

• Controlled spalling is an effective and economical technique for producing high-quality III-V semiconductor thin films.
• This method facilitates the development of cost-effective and efficient solar energy conversion devices based on III-V semiconductors.
• The study highlights the potential of thin-film InP for advanced solar energy applications.