Formation of Composite Structures of Si with A₃B₅ Nanoparticles for Near-Infrared Photoelectronics

Composite silicon (Si) layers containing a synthesized narrow-band gap indium arsenide (InAs) phase are of interest from the viewpoint of extending the optical absorption region and photoresponse of Si to the near- and mid-IR region ( λ=1-3.5 μ m). In this work, we investigate single-crystal Si layers subjected to sequential implantation with In ⁺ and As ⁺ ions followed by thermal annealing in a furnace (solid-phase crystallization) or pulsed nanosecond annealing with a C ⁺ /H ⁺ ion beam (liquid-phase crystallization). By means of scanning electron microscopy, secondary ion-mass spectrometry, X-ray diffraction, optical infrared spectroscopy, and photoconductivity methods, the structural, optical, and photoelectric properties of the composite layers were studied. It has been shown that pulsed annealing leads to a deep diffusion of As atoms into Si up to 1 μ m with formation of a solid solution Si : As, while the In impurity is pushed to the surface. Thermal annealing leads to a slight redistribution of impurities and formation of secondary phases of InAs and In ₂ O ₃ . In both cases, a high electron concentration ( ~2× 10²⁰ cm ⁻³ ) was achieved and an intense absorption band with a maximum at 3.6 μ m was detected. The photoresponse spectra of the mesa diodes at 300 K show a photosensitivity region of 0.5–1.2 μ m comparable with a typical Si photodiode. No photoresponse was detected in the region of 1.2–2.4 μ m.