High-Quality GaSe Single Crystal Grown by the Bridgman Method

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Gallium Selenide (GaSe) is a promising semiconductor material.
• High-quality GaSe crystals are essential for advanced electronic and optoelectronic applications.
• Previous studies faced challenges in achieving high crystalline quality in GaSe.

Purpose of the Study:

• To grow high-quality Gallium Selenide (GaSe) single crystals using the Bridgman method.
• To characterize the crystalline quality, optical properties, and electrical properties of the grown GaSe.
• To fabricate and evaluate few-layer GaSe-based photodetectors.

Main Methods:

• Bridgman crystal growth method.
• X-ray rocking curve analysis to determine crystalline quality (Full Width at Half Maximum - FWHM).
• Infrared (IR) transmittance and low-temperature (9.2 K) photoluminescence spectroscopy.
• Mechanical exfoliation for preparing few-layer GaSe.
• Fabrication and characterization of photodetectors.

Main Results:

• Achieved GaSe crystal with record-low FWHM of 46 arcs, indicating superior crystalline quality.
• Observed high IR transmittance (~66%) and a sharp exciton peak in photoluminescence.
• Grown GaSe exhibited p-type conductance with a resistivity of 10³ Ω/cm and Hall mobility of ~25 cm² V⁻¹ s⁻¹.
• Fabricated few-layer GaSe photodetectors demonstrated an on/off ratio of 10⁴, mobility of 0.4 cm² V⁻¹ s⁻¹, and response time < 60 ms.

Conclusions:

• The Bridgman method successfully produced high-quality GaSe single crystals.
• The exceptional quality of GaSe facilitates the development of high-performance optoelectronic devices.
• Few-layer GaSe photodetectors show significant potential for applications requiring fast and sensitive light detection.