For specific modification of the fundamental optical and photoelectrical properties of silicon transparent for wavelengths beyond 1.1μm, boron ions have been implanted into n-type wafers at doses of 1 х 1013 cm-2–1 х 1015 cm-2 followed by annealing at 900 °C and 1000 °C (20 min). The IR reflection spectra, Raman spectroscopy and scanning electron microscopy data have been compared with the photosensitivity spectra (1.4–2.2 μm) and with the integrated photoresponse in the IR (1.0–4.1 μm) and UV (0.25–0.4 μm) regions. These studies allow for materials engineering to obtain new data on the influence of defect formation on the optical properties of the material and to evaluate the technological conditions for practical application of the modified material.

An attempt is made to analyze and summarize the literature data on hybrid x-ray GaAs pixel detectors designed for medical imaging. Criteria are stated for selecting a semiconductor material. It is shown that GaAs is currently preferable to the other semiconductor materials. Detector figures of merit used to select a semiconductor material and a process technology are listed. Major types of x-ray detector based on bulk-grown or epitaxial GaAs are described, namely, the planar Schottky, the planar p-i-n, and the 3D detector. The influence is considered of different process steps (contact formation, passivation coating, hybridization, etc.) on detector figures of merit. Monolithic technology is briefly discussed.

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The optical and electrical characteristics of p–n photodiodes based on monocrystalline n‐Si (wafers with ρ = 70 and 10 Ohm · cm and SOI) implanted with B+ in the dose range of 1 × 1014–1 × 1015 сm−2 and annealed at 900 °C (20 min) are studied. The p–n structures exhibit photosensitivity in the short‐wavelength infrared region (SWIR) with different maximum intensities depending on dose and n‐Si resistivity. Leakage currents are also dose‐dependent. The character of the SOI spectra is somewhat different. The optical and electrical properties of p–n photodiodes are described in terms of formation of extended defects with deep levels in the bandgap appearing after B implantation and annealing of n‐Si. The importance of the damaged surface layer in the starting material for the observed effects is confirmed experimentally. The relation of the SWIR photoresponse intensity to the content of C and O gettered to the p–n structure surface is revealed. The innovative aspects of technology application are discussed.