Modeling of steady-state field distributions in blocked impurity band detectors

Abstract

Steady-state electric field and carrier distributions are calculated for blocked impurity band (BIB) detectors in the absence of external illumination. The results illustrate the role of space charge in the blocking layer. Calculations are presented for Ge:Ga, though the input is easily modified for other materials. The numerical model allows for observation of the effect of spatial doping variations and interface gradients. The BIB field distribution is highly dependent on the purity and compensation in the blocking layer, as well as interface sharpness. In some cases, space charge effects can cause a collapse of the field at the blocker/absorber interface or the contact and resultant low field regions in the blocking layer.

Terahertz Si:B blocked-impurity-band detectors defined by nonepitaxial methods

“…The reproducible dip in the dark I-V characteristic at 2.1 V is due to a change in field distribution and/or a self-stabilization of the gain process. 9,10 The detector performance of the structures was studied by illuminating the helium-cooled samples with infrared radiation through a polyethylene outer and a diamond inner cryostat window. The solid lines in Fig.…”

Ion-implanted Ge:B far-infrared blocked-impurity-band detectors

“…It would therefore, seem appropriate that the blocking layer of a BIB device should be of similar concentration. However, numerical modeling by Haegel et al [12] has shown that the electric field distribution in the BIB detector creates a more stringent requirement of N A < 10 13 cm À3 for the blocking layer.…”

“…These devices exhibited significant Sb diffusion into the pure substrate during growth. BIB device modeling [12] indicates that the Sb gradient at the absorbing layer -blocking layer interface would increase the electric field in the transition region and reduce the field in the blocking layer. This spike in the electric field at the active layer -blocking layer interface is believed to enhance device breakdown at lower applied biases.…”

Electric field and responsivity modeling for far-infrared blocked impurity band detectors

“…Initial modeling results for field distributions as a function of bias, blocking layer doping, and interface gradient have been presented. 15 The hopping mobility is treated following the approach of Petroff and Stapelbroek 16 for an idealized case where the dopants are uniformly spaced. We use their analytic expression, dependent on the Bohr radius a B of the majority dopants and their concentration N A ͑assuming a p-type device͒,…”