Microsecond lifetimes and low interface recombination velocities in moderately dopednhyphen;GaAs thin films

摘要

We have observed lifetimes greater than 1 mgr;s in moderately doped, thin film,nhyphen;GaAs/Al0.3Ga0.7As double heterostructure membranes formed by etching away the substrate. We attribute these ultralong lifetimes to enhanced photon recycling caused by the removal of the substrate. Nonradiative recombination in the bulk and at the interfaces is very low; the upper limit of the interface recombination velocity is 25 cm/s. Such long lifetimes in GaAs doped atND=1.3times;1017cmminus;3suggest that thinhyphen;film solar cells offer a potential option for achieving very high efficiencies.