Electroabsorption Al0.48In0.52As p-i-n avalanche photodiodes grown by molecular beam epitaxy

The operation of the first Al0.48In0.52As p-i-n avalanche photodiode is reported. The i layer has a background doping ≲10¹⁴/ cm³and the diodes have breakdown voltages in excess of -80 V. A strong enhancement of the photoresponse accompanied by avalanche gain at wavelengths near and beyond the band gap is observed, due to the Franz-Keldysh effect. At short wavelengths, an avalanche gain of 50 was measured. A detailed study of different etches to achieve optimum taper of the mesas was also made.