Avalanche Breakdown Characteristics of Al1-xGaxAs0.56Sb0.44 Quaternary Alloys

Avalanche breakdown characteristics are essential for designing avalanche photodiodes. In this letter, we investigated the effects of adding Ga to Al1-xGaxAs0.56Sb0.44 quaternary alloys. Using p-i-n diodes with a 100-nm i-region and alloy composition ranging from x = 0 to 0.15, we found that the bandgap energy of Al1-xGaxAs0.56Sb0.44 reduces from 1.64 to 1.56 eV. The corresponding avalanche breakdown voltage decreases from 13.02 to 12.05 V, giving a reduction of 64.7 mV for every percent addition of Ga. The surface leakage current was also found to be significantly lower in the diodes with x = 0.10 and 0.15 suggesting that Ga can be added to reduce the surface leakage current while still preserving the lattice match to InP substrate. The data from this letter can be downloaded freely.