Low avalanche noise behaviour in bulk Al_0.8Ga_0.2As

摘要

We report avalanche multiplication measurements on 1 μm thickbulk Al_0.8Ga_0.2As diodes which exhibit low excessnoise. A series of homojunction p-i-n and n-i-p structures with very lowdark currents of ~4 μA/cm² at 0.95 V_bd werecharacterised. Photo-multiplication measurements suggest that M_eh with a k value of ~0.2, smaller than thosereported in other bulk m-V materials, such as GaAs, GaInP, InP and Al_xGa_1-xAs(x⩽0.6). Excess noise resultscorresponding to k≈0.15 were obtained for electron initiatedmultiplication. This broadly corroborates the multiplicationmeasurements and suggests that even in these 1 μm thick structuressome non-local ionization behaviour may be helping to further reduce theexcess noise measured