TRANSIENT PHOTOCONDUCTIVITY AND PHOTOLUMINESCENCE IN InP:Cu

Nonequilibrium photoexcited carrier dynamics in InP:Cu was investigated by two experimental techniques: the time-resolved photoluminescence up-conversion and the transient photoconductivity measurement. Both measurements show that dopmg with copper significantly modifies the photoexcited carrier relaxation in indium phosphide. There are several strong indications that this effect originates from the carrier trapping at metallic precipitates. PACS numbers: 72.40.+w, 78.47.+p, 78.55.-m Semi-insulating Α3B5 semiconduction have numerous important applications as substrates for integrated circuits, microwave and optoelectronic devices. Usually, such materials are obtained by utilizing deep, near-midgap levels compensating shallow impurities. It has been proposed [1] that semi-insulating Α 3 B 5 materials can be created also by introduction of metallic precipitates into the semiconductor, at sufficiently large densities. Originally proposed for explaining unique properties of well-known GaAs 1ayers grown by a low-temperature molecular-beam epitaxy (LT GaAs) the precipitate model is still far from being commonly accepted for that material. In contrary, the latest investigations indicate that the high resistivity and ultrashort carrier lifetimes in LT GaAs can be better explained by the presence of deep, excess-arsenic-related defects [2], a model alternative to the precipitate model. However, it has been observed recently The samples studied were prepared using as-grown nominally undoped, n-type (5 x 10 15 /cm3) InP wafers. Cu was evaporated on both sides of the samples, diffused in clean quartz ampoules and sealed. After diffusion, the samples were rapidly quenched by dropping the ampoules into liquid nitrogen. Any residual Cu was removed from the samples surfaces by a mechanical polishing followed by an etchin