Study on In-Doped CdMgTe Crystals Grown by a Modified Vertical Bridgman Method Using the ACRT Technique

Area of Science:

• Materials Science
• Semiconductor Physics
• Nuclear Instrumentation

Background:

• Cadmium-magnesium-telluride (CdMgTe) is a promising semiconductor for radiation detection.
• Developing high-quality CdMgTe crystals is crucial for effective gamma-ray detection at room temperature.

Purpose of the Study:

• To grow and characterize indium-doped CdMgTe crystals for room temperature gamma-ray detection.
• To investigate the effect of annealing on crystal quality and detector performance.

Main Methods:

• Modified Bridgman method with excess tellurium (Te) was used to grow CdMgTe ingots.
• Characterization techniques included structural analysis, infrared transmittance, photoluminescence, and electrical measurements.
• Gamma-ray detection performance was evaluated using 241Am and 137Cs sources.

Main Results:

• As-grown CdMgTe crystals exhibited a cubic zinc-blende structure with Te-rich inclusions.
• Initial low infrared transmittance and resistivity improved significantly after annealing due to Te inclusion elimination.
• Annealed CdMgTe detectors achieved energy resolutions of 12.7% for 241Am and 8.6% for 137Cs.
• Electron mobility-lifetime product was measured to be 1.66 × 10^-3 cm^2/V.

Conclusions:

• Annealing effectively enhances the crystal quality and performance of indium-doped CdMgTe for radiation detection.
• The developed CdMgTe material shows significant potential for practical room temperature gamma-ray detector applications.