First time demonstration of InP p/sup ++//n/sup ++/ tunnel junction

For the first time an InP p/sup ++//n/sup ++/ tunnel junction is demonstrated. InP tunnel diodes with peak current densities up to 1600 A/cm/sup 2/ and maximum specific resistivities (Vp/1p-peak voltage to peak current ratio) in the range of 10/sup -4/ /spl Omega/.cm/sup 2/ were obtained. This high peak current density is comparable to the highest results previously reported for their lattice matched In/sub 0.53/Ga/sub 0.47/As counterparts. This achievement is very important for InP/InGaAs tandem solar cell design due to the very high peak current density which allows concentrator applications and also because the tunnel junction material being the same as the tandem's top solar cell avoids the optical losses observed when using In/sub 0.53/Ga/sub 0.47/As tunnel junctions. In this paper we discuss the device characteristics and the influence of the growth conditions on its performance.