CdTe X/γ-ray Detectors with Different Contact Materials

Area of Science:

• Materials Science
• Semiconductor Physics
• Radiation Detection Technology

Background:

• High-performance room temperature cadmium telluride (CdTe)-based X/γ-ray detectors are crucial for various applications.
• Optimizing contact materials and deposition techniques is key to enhancing detector performance.
• Existing detectors face limitations in performance and operational range.

Purpose of the Study:

• To develop and investigate heterostructures with various ohmic and Schottky contacts for CdTe detectors.
• To explore the impact of surface pre-treatment on contact properties.
• To analyze current transport mechanisms and optimize detector performance, particularly for p-n junction diodes.

Main Methods:

• Fabrication of heterostructures using DC reactive magnetron sputtering and vacuum thermal evaporation.
• Creation of In/CdTe/Au diodes with a p-n junction via laser-induced doping.
• Analysis of current-voltage (I-V) characteristics and application of transport models (generation-recombination, space-charge limited current, Poole-Frenkel effect).

Main Results:

• Ohmic and Schottky contacts were successfully formed on p-CdTe crystals, with MoO_x exhibiting tunable properties based on surface treatment.
• Transport processes in Schottky diodes were modeled, yielding parameters like trap densities and carrier lifetimes.
• Laser-induced doping in In/CdTe/Au p-n junction diodes extended the operational voltage range and demonstrated high energy resolutions (e.g., 1.6% at 662 keV).

Conclusions:

• Optimized contact engineering and laser-induced doping significantly enhance the performance of CdTe-based radiation detectors.
• The developed In/CdTe/Au p-n junction diodes offer superior energy resolution for X/γ-ray detection.
• These advancements pave the way for more sensitive and reliable CdTe radiation detection systems.