Dependence of zero-bias resistance-area product and quantum efficiency on perimeter-to-area ratio in a variable-area diode array

Abstract

The dependence of the zero-bias resistance-area (RA) product and the quantum efficiency (η) of variable-area diode arrays is numerically calculated by solving the diffusion equation in a cylindrical, three-dimensional geometry in the thick base approximation. The calculation is done for long-wavelength IR HgCdTe n + -on-p diffusion-limited photodiodes at 77 K. The inverse resistance-area product 1/(RA) and the square root of the quantum efficiency, η 1/2 , are plotted against the perimeter-to-area (P /A) ratio. The 1/RA results are fitted to a quadratic dependence on the P /A ratio. The dependence of the 1/RA on the minority carrier diffusion length, the junction depth and the surface recombination velocity (SRV) is evaluated. An empirical expression is proposed that largely accounts for the dependence of the coefficients of the quadratic on these parameters and is more general than those used in previous studies. The results are also in reasonable agreement with the results of Briggs, expressed in terms of the parameter f 3D , that are valid for zero junction depth and zero SRV. The slope of the quantum efficiency versus P /A plot, which is approximately a straight line, is related to an effective length L opt , that also depends on the diffusion length, junction depth, SRV and the absorption coefficient α. The parameter L opt varies as α 1/2 .

Proton Irradiation Effects on the Performance of III-V-Based, Unipolar Barrier Infrared Detectors

“…Other studies have shown is dependent on junction depth, surface recombination velocity and the absorption coefficient, as well as on the minority carrier diffusion length ; therefore, should only be treated as a phenomenological fitting factor that represents an effective diffusion length. [10] [11] Judging by the fit qualities of the measurements in these experiments referred to, (1) appears to be a valid means of assessing the optical response of these detectors even as was expected to decrease below the absorber length with increasing proton fluence . Both optical and electrical characterization results for several of the PECs presented in this work were compared to that of companion FPAs and there was strong agreement between those results.…”

“…[17] [18] would now have a -dependence since a linear increase in with increasing is still expected. Formally, damage factor analysis typically only considers linear changes with and thus, formally-speaking, it is that should be examined for , where related to by (10) of a non-ideal nBn is considered next. If a depletion region of width exists in the detector's narrow gap layer, due either to the detector's design or from operating at a slightly higher than intended reverse bias voltage, then a generation-limited dark current density component , given by (11) will also be present.…”

“…Thus, any changes in the tunneling-dominated region of the dark current I-V relationship may be indicative of increasing . Comparing expressions (8), (10), and (13) indicates that is related to the fundamental radiation-tolerance of the detectors' material and design via the term in each. However, these expressions also indicate that the coefficients of (i.e.…”

LWIR Photodiodes and Focal Plane Arrays Based on Novel HgCdTe/CdZnTe/GaAs Heterostructures Grown by MBE Technique

“…The quantum efficiency η and R 0 A product (R 0 -differential resistance at 0 bias voltage; Adiode area) was numerical calculated for p-P MCT HES taking into account only diffusion current in which the lateral diffusion current contribution becomes essential [21,22]. The diffusion current is determined from decision of stationary continuity equation for excess electron in р range.…”

Controlling dark current in type-II superlattice photodiodes

“…On the right side we extract the effective sidewall resistivity, q Surface , and bulk-limited dynamic impedance-area product (R eff A) Bulk by fitting the dependence of (R eff A) À1 on the perimeter-to-area ratio (P/A) for a series of diodes with diameters varying from 100 to 400 lm, as described in Ref. [16]:…”