MBE Growth of High-Quality HgCdSe for Infrared Detector Applications

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• HgCdTe is a standard for infrared detectors.
• HgCdSe is a potential alternative material.
• Developing new materials is crucial for advanced infrared detection.

Purpose of the Study:

• To investigate the growth of high-crystalline-quality HgCdSe.
• To fabricate and characterize the first HgCdSe-based mid-wave infrared detectors.
• To assess the potential of HgCdSe as an alternative to HgCdTe.

Main Methods:

• Molecular Beam Epitaxy (MBE) growth on GaSb (211)B substrates.
• Optimization of MBE growth parameters, including substrate thermal cleaning.
• Characterization of material quality using XRD and assessment of detector performance at 77 K.

Main Results:

• Achieved high-quality HgCdSe with a record XRD FWHM of ~65 arcsec.
• Demonstrated HgCdSe n-type material with a minority carrier lifetime of ~1.19 µs and mobility of ~1.6 × 10⁴ cm²/Vs.
• Fabricated HgCdSe photoconductor with a 4.2 µm cut-off wavelength and peak detectivity of ~1.2 × 10⁹ cmHz¹/2/W at 77 K.

Conclusions:

• HgCdSe shows significant potential for next-generation infrared detectors.
• The material offers advantages in cost and large-area substrate compatibility.
• Further optimization is needed to match the performance of state-of-the-art HgCdTe detectors.