Improved performance of strained InGaAs/GaAs photodiodes grown on patterned GaAs substrates by molecular beam epitaxy

We have experimentally studied the photoresponse characteristics of strained In,Gar _ XAs (0.05<~<0.20) p-i-n photodiodes grown in small holes etched in GaAs substrates where the thickness of the i region exceeds the critical thickness. The diodes exhibit enhanced quantum efficiency and no degradation of the temporal response compared with devices grown on planar substrates, indicating that reduced area growth may be a useful technique for making optoelectronic devices with strained-layer structures.