Position-sensitive multi-wavelength photon detectors based on epitaxial InGaAs/InAlAs quantum wells

The QW devices have been tested with collimated monochromatic X-ray beams from synchrotron radiation. A rise in the current noise with positive bias was observed, which could be due to deep traps for hole carriers. Therefore, an optimized negative bias was chosen to minimize dark currents and noise. A decrease in charge collection efficiency was experienced as the beam penetrates into deeper layers, where a dislocation network is present. The prototype samples showed that individual currents obtained from each quadrant allow the position of the beam to be monitored for all the utilized energies. These detectors have a potential to estimate the position of the beam with a precision of about 10 µm.