InGaAs x-ray photodiode for spectroscopy

A prototype In0.53Ga0.47As p+ -i-n+ X-ray photodiode, fabricated from material grown by metalorganic vapour phase epitaxy, was investigated as a novel detector of X-rays. The detector was connected to a custom low-noise charge sensitive preamplifier and standard readout electronics to produce an X-ray spectrometer. The detector and preamplifier were operated at a temperature of 233 K (-40 °C). An energy resolution of 1.18 keV ± 0.06 keV Full Width at Half Maximum at 5.9 keV was achieved. This is the first time InGaAs (GaInAs) has been shown to be capable of spectroscopic photon counting X-ray detection.