Abstract: The present invention improves the resolution and accuracy of the presently known two-dimensional position sensing detectors and delivers improved performance in the 1.3 to 1.55 micron wavelength region. The present invention is an array of semiconductor layers with four electrodes, the illustrative embodiment comprising a semi-insulating substrate semiconductor base covered by a semiconductor buffered layer, the buffered layer further covered by a semiconductor absorption layer and the absorption layer covered with a semiconductor layer. Four electrodes are placed on this semiconductor array: two on the top layer parallel to each other and near the ends of opposite edges, and two etched in the buffered layer, parallel to each other and perpendicular to the first set. The layers are doped as to make a p-n junction in the active area. Substantially all the layers, excepting the semi-insulating substrate layer, are uniformly resistive.

Abstract: The present invention improves the resolution and accuracy of the presently known two-dimensional position sensing detectors and delivers improved performance in the 1.3 to 1.55 micron wavelength region. The present invention is an array of semiconductor layers with four electrodes, the illustrative embodiment comprising a semi-insulating substrate semiconductor base covered by a semiconductor buffered layer, the buffered layer further covered by a semiconductor absorption layer and the absorption layer covered with a semiconductor layer. Four electrodes are placed on this semiconductor array: two on the top layer parallel to each other and near the ends of opposite edges, and two etched in the buffered layer, parallel to each other and perpendicular to the first set. The layers are doped as to make a p-n junction in the active area. Substantially all the layers, excepting the semi-insulating substrate layer, are uniformly resistive.