GaN intermediate band solar cells with Mn-doped absorption layer

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Investigating optical properties of Manganese (Mn)-doped Gallium Nitride (GaN) layers.
• Understanding the impact of Mn concentration on GaN's electronic band structure.

Purpose of the Study:

• To analyze the effect of Mn doping on GaN optical properties.
• To evaluate Mn-related energy states within the GaN bandgap.
• To assess the performance enhancement of GaN-based solar cells with Mn doping.

Main Methods:

• Metalorganic vapor phase epitaxy (MOVPE) for growing Mn-doped GaN layers.
• Optical transmittance and electroluminescence (EL) spectroscopy.
• Fabrication and testing of GaN-based solar cells with and without Mn doping.

Main Results:

• Mn-doped GaN layers exhibit a transmittance dip around 820 nm due to Mn-related energy states.
• EL spectra confirm the presence of Mn-related energy states within the GaN bandgap.
• Mn-doped GaN solar cells show enhanced photocurrent and a 10x increase in short-circuit current compared to undoped cells.

Conclusions:

• Mn doping introduces intermediate energy states in GaN, enabling sub-bandgap absorption.
• These Mn-related states significantly boost the performance of GaN-based solar cells.
• The study demonstrates a viable method for improving solar cell efficiency using Mn-doped GaN.