%0 Journal Article
%T Contribution of Series Resistance in Modelling of High-Temperature Type II Superlattice p-i-n Photodiodes
%A Jarosˋaw Wr車bel
%A Piotr Martyniuk
%A Antoni Rogalski
%J Advances in Optical Technologies
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/926365
%X We analyze some of the consequences of omitting series resistance in InAs/GaSb p-i-n T2SL photodiode dark current modelling, using simplified p-n junction model. Our considerations are limited to generation-recombination and diffusion-effective carrier lifetimes to show the possible scale of over- or underestimating photodiodes parameters in high-temperature region. As is shown, incorrect series resistance value might cause discrepancies in and 's estimations over one order of magnitude. 1. Introduction Type II superlattices (T2SLs), especially InAs/GaSb, are very promising materials for both uncooled as well as cooled midwavelength infrared (MWIR) and long wavelength infrared (LWIR) photodetectors [1]. Relative easiness of controlling band offset causes them to be used in different types of structures [2]. Especially, introducing unipolar barriers in various designs based on type II SLs drastically changed the architecture of infrared detectors. At present, the InAs/GaSb T2LSs are considered to be an alternative to the HgCdTe IR material systems [1] and a candidate for the third-generation IR detectors [3]. However, InAs/GaSb T2SL is in an early stage of development. Problems exist in material growth, processing, substrate preparation, and device passivation [4每6]. Moreover, correct interpretations of measured detector characteristics are often difficult due to fact that T2SLs＊ band structures are much more complicated than bulk materials [7]. From this reason, there have been developed many simplified models [8每13], which assume that T2SL electrical parameters are mainly dependent on energy difference between first conduction and heavy hole miniband (which is treated as an effective bandgap). For an approximative describing of the detector transport mechanisms, the well-known standard theory of p-n junction is used [2, 14]. Recently published results of our group show that usage of this method can give very good fitting between theoretical predictions and experimental data in a wide range of bias voltage (from 每1.6 to +0.3ˋV) and temperature (from 77 to 240ˋK) for p-i-n and nBn devices [15每17]. It appears that good agreement between both types of results is possible if the influence of series resistance ( ) is taken into consideration, what might be essential in a thermoelectrically cooled (TE) photodetectors (in temperature range above 180ˋK). In this paper we present the consequences of omitting in the dark current modelling of p-i-n T2SL junctions, often met in literature. These consequences are shown on an example of temperature dependence of two
%U http://www.hindawi.com/journals/aot/2012/926365/