Photovoltaic Characteristics of GaSe/MoSe₂ Heterojunction Devices

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials with atomic layer thickness are promising for future electronics and optoelectronics.
• Transition metal monochalcogenides and dichalcogenides, like GaSe and MoSe2, possess band gaps, enabling semiconductor properties in single layers.
• These 2D semiconductors are candidates for novel flexible optoelectronic applications.

Purpose of the Study:

• To investigate the photovoltaic characteristics of a heterojunction device formed by p-type gallium selenide (GaSe) and n-type molybdenum diselenide (MoSe2).
• To evaluate the performance of the GaSe/MoSe2 heterojunction under varying light intensities.

Main Methods:

• Fabrication of the heterojunction device by mechanically peeling and transferring 2D GaSe and MoSe2 onto a substrate with pre-fabricated titanium electrodes.
• Measurement of current-voltage characteristics of the GaSe/MoSe2 heterojunction device under dark and light irradiation conditions using a solar simulator.
• Systematic variation of light irradiation intensity from 0.5 to 1.5 suns.

Main Results:

• The GaSe/MoSe2 heterojunction device demonstrated increased short-circuit current and open-circuit voltage with increasing light intensity.
• Under 1.5 suns illumination, the device achieved an open-circuit voltage of 0.41 V.
• The energy conversion efficiency of the device reached 0.46% under 1.5 suns illumination.

Conclusions:

• The GaSe/MoSe2 heterojunction exhibits promising photovoltaic properties for optoelectronic applications.
• The performance of the device scales with light intensity, indicating potential for solar energy harvesting.
• Further optimization of 2D material-based heterojunctions could lead to advancements in flexible electronics.