Fabrication of GaAs photodiode using laser selective area epitaxy

Laser-assisted chemical vapor deposition offers a new approach for the integration of optoelectronic devices. We report for the first time the selective deposition and fabrication of a GaAs p-i-n photodetector. The detector, fabricated on a 200×200 μm mesa, shows an impulse response with a full width at half maximum of 150 ps and external quantum efficiency (no AR coating) of 60% both at 0 and −1.4 V bias. These results show that the p-i-n detector has a performance comparable to that achieved by metalorganic chemical vapor deposition and molecular beam epitaxy for similar device dimensions.