High-density, planar Zn-diffused InGaAs/InP photodetector arrays with extended short-wavelength response

A 512-element InGaAs photodetector array with low leakage, usable optical response from 600 to 1700 nm, and an element separation of 4.5 mu m was developed. Electrical characterization of individual photodiode elements revealed a dark current of <1.0 nA at -4.0 V and a dynamic resistance of >400 M Omega at 0 V. These values are indicative of the high electrical isolation of individual elements despite the close proximity. Optical responsivity with no antireflection coating was 0.28 A/W at 600 nm and increased approximately linearly to 0.94 A/W at 1600 nm. Optical crosstalk between adjacent photodetectors was less than 1.0% at 1300 nm.