GaAs detectors for medical imaging

GaAs Pixel-Detector Technology for X-ray Medical Imaging: A Review

“…Nevertheless, some other workers argue that GaAs doped heavily with Cr is suitable for the purpose because Cr doping compensation will free the material from the adverse effects of EL2 centers while providing a uniform field distribution over the substrate thickness with any type of metal contacts [27,28]. In those studies, µ = 4000 cm 2 V -1 s -1 and ρ = 10 8 to 10 9 Ω cm were obtained by high-temperature diffusion Cr doping of ntype wafers of LEC-grown GaAs.…”

“…Thick epitaxial GaAs films are mostly grown by liquid-phase epitaxy [18,28] or chemical vapor deposition [6,17,30], particularly metal-organic one. Liquidphase epitaxy can yield films up to 150-250 µm thick, but these tend to show an undulating surface.…”

“…In other studies, a Cr-compensated i-layer was grown by liquid-phase epitaxy (LPE) on an n + -substrate, and the p + -layer was produced by VPE [18,28]. The i-layer thickness was 150-250 µm and could be increased to 400 µm by repeated growth.…”

Selective epitaxial growth of GaAs by current controlled liquid phase epitaxy

“…Recently, Gallium Arsenide (GaAs) has got its attention in medical X-ray imaging in the range 5-30 keV [2][3][4][5][6][7][8][9]. The commercial imagers were a combination of a scintillator material coupled to an array of Si Silicon (Si) photodiodes.…”

Impulse Response of GaAs Radiation Imaging Detectors

“…In works [1,2] it was shown that GaAs compensated by Cr, has higher efficiency of the charge collection, in comparison with LEC SI GaAs. However, there are no data on model of nonequilibrium charge carriers in the detector structures based on GaAs, compensated by Cr, as cause statement of the given study.…”