Radical assisted metalorganic chemical vapor deposition of CdTe on GaAs and carrier transport mechanism in CdTe/n-GaAs heterojunction

temperature range of 150‐300 °C. The grown films have high resistivity in the order of 10 7 V cm for the entire growth range. Applicability of this heteroepitaxial CdTe layer on n-GaAs as an x-ray detector was then investigated. The carrier transport mechanism of the CdTe/ n-GaAs heterojunction was studied by means of current‐voltage measurements at different temperatures. The forward current was characterized by multitunneling capture-emission current and space charge limited current. The reverse current was considered as the generation current from the heterojunction interface states through the analysis of capacitance‐voltage measurement. It is found that for devices using minority carriers, this heterojunction alone is not useful because of the high concentration of interface states. A suitable modification, like an isotype heterojunction between GaAs and CdTe before forming the p-n junction, seems to be necessary. © 1998 American Institute of Physics. @S0021-8979~98!03405-7#

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