Main Objectives

The objective of research package WP3 is to develop and investigate gallium nitride doped with selected rare-earth ions (RE) for applications in single-photon sources (Single-Photon Sources – SPS) and integrated quantum sensors.

Scientific and technological tasks include:

• Precision control over rare-earth ion incorporation (erbium – Er, terbium – Tb) into the GaN crystalline matrix via ion implantation.
• Optical activation of luminescent centers using Ultra-High Pressure Annealing under nitrogen atmosphere (UHPA), preventing GaN decomposition at elevated temperatures.
• Characterization and annealing of radiation-induced lattice damage in GaN.
• High-resolution spectroscopy of individual emission centers and assessment of room-temperature quantum coherence.

Research Strategy and Innovation

Native, dislocation-free GaN bulk crystals and epitaxial layers developed at IHPP PAS offer a globally unique platform for engineering quantum emitters. Unlike heteroepitaxial structures grown on foreign substrates (e.g., sapphire, silicon), the near-complete absence of extended dislocations ensures an exceptionally low non-radiative noise background and enhanced optical stability.

Fig. 1. Technological and characterization route for rare-earth doped GaN: ion implantation, UHPA annealing, and advanced luminescence spectroscopy.

Fig. 2. Proposed device concepts for electrical excitation of rare-earth luminescent centers in gallium nitride.

Current Status and International Collaboration

• Implantation Parameter Tuning: Initial doping profiles and fluences for Er and Tb ions across various beam energies were determined through stopping-and-range simulations.
• UHPA High-Pressure Processing: High-pressure autoclaves were prepared for annealing runs at pressures of 10–20 kbar and temperatures exceeding 1200°C.
• Defect Characterization: To evaluate vacancy creation and annihilation kinetics following implantation, collaboration was established with Prof. Filip Tuomisto’s group at the University of Helsinki using Positron Annihilation Spectroscopy (PAS).

Next Steps

• Executing planned ion implantation series with Er and Tb on selected high-perfection GaN substrates.
• Performing high-pressure UHPA annealing and optimizing activation temperatures and residence times.
• Temperature-dependent photoluminescence (PL) spectroscopy to identify and isolate targeted dopant transitions.