Parameter determination from resistance-voltage curve for long-wavelength HgCdTe photodiode

A data-processing approach has been developed to obtain device parameters from resistance-voltage (R-V) curves measured on long-wavelength HgCdTe n-on-p photodiodes. The physical model used for R-V curve fitting includes the dark current mechanisms induced by diffusion, generation recombination, trap-assisted tunneling, and band-to-band tunneling. Moreover, the series resistance effect is also taken into account. Six parameters, which include the dopant density N-d in the n region, the ratio of mobility to lifetime of electrons mu(n)/tau(n) in the p region, the effective lifetime tau(0) in the depletion region, the relative energy position of trap level E-t/E-g and its density N-t in the depletion region, and the series resistance R-s, can be extracted from measured R-V curves. The fitting procedure has been presented in detail and the error ranges of the extracted parameters have been discussed. By fitting to the R-V characteristics of three long-wavelength devices with different Cd compositions, the applicability of our data-processing approach has been verified for obtaining those basic parameters. (c) 2006 American Institute of Physics.