Numerical Simulation and Analytical Modeling of InAs nBn Infrared Detectors with p-Type Barriers

In this paper we present the status of HgCdTe barrier detectors with an emphasis on technological progress in metalorganic chemical vapor deposition (MOCVD) growth achieved recently at the Institute of Applied Physics, Military University of Technology. It is shown that MOCVD technology is an excellent tool for HgCdTe barrier architecture growth with a wide range of composition, donor/acceptor doping, and without post-grown annealing. The device concept of a specific barrier bandgap architecture integrated with Auger-suppression is as a good solution for high-operating temperature infrared detectors. Analyzed devices show a high performance comparable with the state-of-the-art of HgCdTe photodiodes. Dark current densities are close to the values given by ''Rule 07'' and detectivities of non-immersed detectors are close to the value marked for HgCdTe photodiodes. Experimental data of longwavelength infrared detector structures were confirmed by numerical simulations obtained by a commercially available software APSYS platform. A detailed analysis applied to explain dark current plots was made, taking into account Shockley-Read-Hall, Auger, and tunneling currents.

Section: Resultsmentioning

confidence: 80%

Status of HgCdTe Barrier Infrared Detectors Grown by MOCVD in Military University of Technology

Kopytko

Jóźwikowski

Martyniuk

et al. 2016

“…We note there has been extensive and detailed theoretical modeling and analysis of the nBn structure in the literature. [25][26][27][28][29] Here we concentrate on unintended hole barriers which can hinder minority carrier collection.…”

Section: Minority Carrier Extraction In N-type Unipolar Barrier Inframentioning

confidence: 99%

Theoretical Aspects of Minority Carrier Extraction in Unipolar Barrier Infrared Detectors

Ting

Soibel

Höglund

et al. 2015

We have examined, theoretically, minority carrier collection in unipolar barrier infrared photodetectors. In barrier infrared detectors, for example the nBn, the unipolar barrier should block only majority carriers and allow unimpeded flow of minority carriers. However, an imperfect barrier would also block minority carriers, resulting in higher than expected turn-on bias. Minority carrier blocking can be caused by barrier doping or unintended band offset between the barrier and the absorber. The distinct manner in which these two mechanisms affect device performance were investigated. We found that introduction of an appropriate amount of barrier doping can reduce depletion dark current without increasing turn-on bias. We examined the effects of band structure on conductivity effective masses when the n-type absorber was a type-II superlattice (T2SL). We showed that for a long-wavelength infrared InAs/GaSb T2SL the vertical conductivity hole effective mass can be much smaller than that predicted by the simple band-edge effect mass picture, implying that the vertical hole mobility estimated from the band-edge effective mass can be unduly pessimistic.

“…5,7,10,[13][14][15][16] While the idea of the nBn design originated with bulk materials, 5,17 its demonstration using T2SL-based materials facilitates experimental realization of the nBn concept with improved control of band-edge alignments. 18 Unipolar barriers can also be inserted into the conventional p-n photodiode architecture.…”

Section: Benefits and Limitations Of Unipolar Barrier Photodetectorsmentioning

confidence: 99%

Mid-Wavelength Infrared nBn for HOT Detectors

Rogalski

Martyniuk

2014

Recently, new strategies to achieve high-operating-temperature (HOT) detectors have been proposed, including barrier structures such as nBn devices, unipolar barrier photodiodes, alternative materials such as superlattices, and multistage (cascade) infrared devices. In the case of nBn detectors, the barriers must be correctly engineered and correctly located in the device structure to achieve optimal performance. This paper presents the limitations of barrier unipolar devices and the progress in their development for HOT operation in the mid-wavelength infrared range. Their performance is compared with state-of-the-art HgCdTe photodiodes.