P ON N HETEROSTRUCTURES IN HGCDTE ON GAAS ANALYZED BY TRANSMISSION ELECTRON-MICROSCOPY

The structure of p on n HgCdTe heterostructures grown by molecular bea m epitaxy on GaAs(211) B substrates have been analyzed by transmission electron microscopy. The HgCdTe absorber layer is grown on a CdTe buf fer and doped n type with indium. The p-type arsenic dopant is incorpo rated in the heterostructure during growth into a HgTe/CdTe cap superl attice and annealed ex situ to form the random alloy. The active p-n j unction is formed below the as-grown p-n interface as a result of As d iffusion. We compare the device performance with the microstructural d efects in the various regions of the device layers and show the import ance of dislocations near the p-n junction as well as in the n layer i n influencing device quality.