Study of As4 beam induced P-As exchange reaction on InP surface by photoluminescence and X-ray diffraction

Presents the result of a detailed investigation on the P-As exchange reaction which takes place on the InP surface when it is exposed to As₄ beam. Characterization was made by growing an additional InP cap layer on the As₄ beam exposed InP surface and analyzing the resultant InP/InAs_xP_1-x/InP single quantum well (QW) structure by photoluminescence (PL) and X-ray diffraction (XRD) measurements. The results provide quantitative data on the rate and depth of the exchange reaction as a function of growth parameters which may be useful for MBE growth of P and As containing heterostructures. XRD technique has shown that the average depth of exchange reaction is not limited to the top monolayer, but penetrates as deep as 5.5 ML for long exposure. The PL results have shown that an exchange efficiency is as high as 90-95%. The splitting in PL peaks was observed when the reaction depth exceeded 2 ML, indicating an increase of fluctuation of the reaction depth for the strain relief process. Both the reaction depth and the fluctuation of the well thickness increases with the increase of As exposure time but the reaction depth tends to saturate when the average exchange depth reaches 5-6 MLs