Abstract

Optical detectors are important in integrated optics, and monolithic integration of photodetectors on waveguides has become an attractive technique. High-speed response and high photoconductor sensitivity are required for optoelectronic devices. Because of the high absorption coefficient and low transit time for the photogenerated carriers in a Schottky configuration, hydrogenated amorphous silicon (a-Si:H) is an interesting material for low-cost integrated photodetectors. It can easily be deposited in thin films and at low temperature (250°C) on Si or GaAs. We present photodetectors integrated on a slab ion-exchanged glass waveguide.¹ By using capacitance measurements with a Schottky photodetector, we have deduced the semiconductor properties through modelling and have calculated an RC time constant of 17.6 ns. The measured parameters with shortpulse (4 ns) laser light at 0.63μm are a sensitivity of 22.35 mA/W, a detectivity D^* = 3.09 × 10¹⁰ cm Hz^1/2/W, and a response time of 30 ns FWHM under zero-bias conditions. The fabrication process and characterization results will be presented in detail. The performance of the P-I-N device will be compared with the Schottky device, and its advantages will be discussed.

© 1990 Optical Society of America