Optical properties of HgTe/CdTe superlattices in the normal, semimetallic, and inverted-band regimes

Yang, Zhiyao; Yu, Zhonghai; Lansari, Y.; Hwang, Sheue‐Ling; Cook, J. W.; Schetzina, J. F.

doi:10.1103/physrevb.49.8096

Cited by 29 publications

(11 citation statements)

References 17 publications

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“…K was shown to be temperature dependent, i.e., dK/dT = À0.40 meV K À1 . 19 Consequently these values at liquid helium temperatures, in particular 650 meV, are in reasonably good agreement with room temperature values, 16,17 within published experimental uncertainties, e.g., ± 60 meV.…”

Section: Methods Of Calculationsupporting

confidence: 66%

“…15 Others determined much larger values of 530 meV and 450 meV at room temperature from k-resolved ultraviolet and x-ray photoemission at k = 0, and infrared absorption results, respectively. 16,17 Magneto-optical experiments 18 and photoluminescence spectra at liquid helium temperatures 19 suggested values of 800 meV and 650 meV, respectively. K was shown to be temperature dependent, i.e., dK/dT = À0.40 meV K À1 .…”

Section: Methods Of Calculationmentioning

confidence: 96%

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Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

Kopytko

Wróbel

Jóźwikowski

et al. 2014

Journal of Elec Materi

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Design of practically realizable unipolar HgCdTe nBn photodetectors has been studied in detail by numerical analysis. The simulations reported herein reveal that, by optimization of barrier doping, dark current levels can be reduced and collection efficiency substantially improved. It is shown that p-type doping of the barrier layer can significantly reduce the effective potential barrier arising from the valence band offset between the absorber and barrier regions, thus enabling HgCdTe nBn detector operation under near zero-bias conditions. However, relatively high electric fields in the space charge regions near the barrier/absorber interface result in enhanced trapassisted Shockley-Read-Hall thermal generation. Our calculations indicate that nBn HgCdTe detectors with barriers engineered by use of HgTe/ Hg 0.05 Cd 0.95 Te superlattices have, potentially, substantially better valence band alignment without the need for p-type doping.

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Section: Methods Of Calculationsupporting

confidence: 66%

Section: Methods Of Calculationmentioning

confidence: 96%

Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

Kopytko

Wróbel

Jóźwikowski

et al. 2014

Journal of Elec Materi

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“…The HSE functional yields a VBO of 0.53 eV in contrast to previous self-consistent calculations of 0.27 eV, 24 0.22 eV, 25 and 0.37 eV. 26 HSE is in excellent agreement with the more recent experimental values of 0.53±0.06 eV 12 and 0.55±0.05 eV 13 in contradiction with earlier x-ray and ultraviolet photoelectron spectroscopy which provide a VBO around 0.35 eV. [27][28][29] Eich et al 12 demonstrate that an accurate treatment of the band dispersion in HgTe at the valence band edge is necessary for a correct measurement of the VBO leading to the higher observed VBO.…”

Section: Resultscontrasting

confidence: 38%

“…HSE also achieves a valence band offset (VBO) of 0.53 eV for HgTe/CdTe(001) agreeing with the more recent experimental data and settling a controversy on the VBO. 12,13 Figure 1(a) describes a typical cubic trivial bandgap insulator (e.g., CdTe) with spin-orbit splitting. The conduction states exhibit s-like orbital symmetry and the Γ point possesses Γ 6 (twofold-degenerate) symmetry.…”

Section: Introductionmentioning

confidence: 99%

Accurate electronic properties for (Hg,Cd)Te systems using hybrid density functional theory

Nicklas

Wilkins

2011

Phys. Rev. B

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Hybrid screened density functional theory better describes the electronic structure of HgTe, CdTe, and HgCdTe systems in comparison with standard density functional theory. The newer hybrid functional reproduces the band inversion in the popular HgCdTe alloy justifying it as a better method than standard density functional theory in the search for new topological insulators. In addition, the 0.53 eV valence band offset obtained using the hybrid functional supports the recently observed higher band offset in the HgTe/CdTe heterostructure.

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“…Published VBO values span from 40 meV to 800 meV at liquid-helium temperature. 24,25 Becker et al and Spicer et al…”

Section: Bird Hgcdte Band Alignment and Srh Gr Suppressionmentioning

confidence: 99%

Theoretical Modeling of HOT HgCdTe Barrier Detectors for the Mid-Wave Infrared Range

Martyniuk

Gawron

Rogalski

2013

Journal of Elec Materi

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This paper reports on theoretical modeling of medium-wavelength infrared HgCdTe barrier infrared detector (BIRD) photoelectrical performance. BIRD HgCdTe detectors were simulated with the commercially available software APSYS. Detailed analysis of the detector performance such as dark current, photocurrent, resistance-area product, detectivity versus applied bias, operating temperature, and structural parameters (absorber doping, barrier composition) was performed to determine the optimal operating conditions. It is shown that higher operation temperature conditions achievable with commonly used thermoelectric coolers allow detectivities of D = 9.5 9 10 10 cmHz 1/2 /W and D * = 1.5 9 10 11 cmHz 1/2 /W at T = 200 K to be obtained for the correct absorber doping for nB n nn + and nB n pn + , respectively. R 0 A for the nB n nn + detector was found to range from 200 X cm 2 to 0.6 X cm 2 at T = 200 K to 300 K, respectively.Key words: HgCdTe, unipolar barrier, nB n n(p), nB n n(p)n + , Auger suppression, photoelectric gain INTRODUCTIONPhotodetectors designed for the mid-wave infrared (MWIR, 3 lm to 5 lm) region meeting the requirements for higher operation temperature (HOT) conditions are important in a variety of civilian and military applications. The key condition which must be fulfilled to design a HOT IR detector is to achieve both low dark current and high quantum efficiency (QE). In standard p-n MWIR photodiodes operating under HOT conditions, the dark current is mostly produced by the Shockley-ReadHall (SRH) generation-recombination (GR) process, Auger, and both: band-to-band (BTB)/trap-assisted tunneling (TAT). [1][2][3] Unfavorable SRH and leakage current components can be suppressed by appropriate selection of barriers (wide-energy-gap materials) incorporated into the detector structure. 4 The barrier selection plays a decisive role due to the lattice constant matching of the detector's constituent layers, the barrier height in both conduction and valence bands (connected directly to the band alignment) being difficult to control from a technological viewpoint.Currently, among barrier IR detectors (BIRDs), the leading position is occupied by devices called unipolar barrier infrared detectors (UBIRDs). A III B V family compounds emerged to play a dominant role in the design of UBIRDs due to a nearly zero band offset in the valence band (e.g., GaSb, InAs 1Àz Sb z cap layers, InAs 1Ày Sb y active region, AlAs 1Àx Sb x barrier). 5 Type II superlattices (T2SLs) of InAs/GaSb with AlGaSb/T2SL barriers (with tunneling and inherited Auger GR process suppression) and more sophisticated structures, such as the ''W'' (InAs/GaInSb/InAs/AlGaInSb), ''M'' (GaSb/ InAs/GaSb/AlSb), and recently presented ''N'' (AlSb/ GaSb/InAs) structures, have also shown promise for HOT conditions. 6-10 The success of T2SLs has resulted from the unique inherited capabilities of the new artificial material with completely different physical properties in comparison with the constituent layers and the nearly zero valence band offsets leading ...

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Optical properties of HgTe/CdTe superlattices in the normal, semimetallic, and inverted-band regimes

Cited by 29 publications

References 17 publications

Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

Accurate electronic properties for (Hg,Cd)Te systems using hybrid density functional theory

Theoretical Modeling of HOT HgCdTe Barrier Detectors for the Mid-Wave Infrared Range

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