Center for Quantum Devices - Most Downloaded Journal Articles

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12.	Passivation of Type-II InAs/GaSb Superlattice Photodiodes A. Gin, Y. Wei, J. Bae, A. Hood, J. Nah, and M. Razeghi International Conference on Metallurgical Coatings and Thin Films (ICMCTF), San Diego, CA; Thin Solid Films 447-448-- January 30, 2004 ...[Visit Journal] Recently, excellent infrared detectors have been demonstrated using Type-II InAs/GaSb superlattice materials sensitive at wavelengths from 3 μm to greater than 32 μm. These results indicate that Type-II superlattice devices may challenge the preponderance of HgCdTe and other state-of-the-art infrared material systems. As such, surface passivation is becoming an increasingly important issue as progress is made towards the commercialization of Type-II devices and focal plane array applications. This work focuses on initial attempts at surface passivation of Type-II InAs/GaSb superlattice photodiodes using PECVD-grown thin layers of SiO₂. Our results indicate that silicon dioxide coatings deposited at various temperatures improve photodetector resistivity by several times. Furthermore, reverse-bias dark current has been reduced significantly in passivated devices. [reprint (PDF)]
12.	Background limited performance of long wavelength infrared focal plane arrays fabricated from M-structure InAs-GaSb superlattices P.Y. Delaunay, B.M. Nguyen, D. Hoffman, E.K. Huang, and M. Razeghi IEEE Journal of Quantum Electronics, Vol. 45, No. 2, p. 157-162.-- February 1, 2009 ...[Visit Journal] The recent introduction of a M-structure design improved both the dark current and R₀A performances of Type-II InAs-GaSb photodiodes. A focal plane array fabricated with this design was characterized at 81 K. The dark current of individual pixels was measured between 1.1 and 1.6 nA, 7 times lower than previous superlattice FPAs. This led to a higher dynamic range and longer integration times. The quantum efficiency of detectors without antireflective coating was 74%. The noise equivalent temperature difference reached 23 mK, limited only by the performance of the testing system and the read out integrated circuit. Background limited performances were demonstrated at 81 K for a 300 K background. [reprint (PDF)]
12.	Phase-matched optical second-harmonic generation in GaN and AlN slab waveguides D.N. Hahn, G.T. Kiehne, G.K.L. Wong, J.B. Ketterson, P. Kung, A. Saxler and M. Razeghi Journal of Applied Physics 85 (5)-- March 1, 1999 ...[Visit Journal] Phase-matched optical second-harmonic (SH) generation was observed in GaN and AlN slab waveguides. Phase matching was achieved by waveguide modal dispersion. By tuning the output wavelength of an optical parametric amplifier, several phased-matched SH peaks were observed in the visible spectrum covering blue to red wavelengths. The peak positions are in agreement with the values calculated using the dispersive refractive indices of the film and substrate materials. [reprint (PDF)]
12.	Near bulk-limited R0A of long-wavelength infrared type-II InAs/GaSb superlattice photodiodes with polyimide surface passivation Andrew Hood, Pierre-Yves Delaunay, Darin Hoffman, Binh-Minh Nguyen, Yajun Wei, Manijeh Razeghi, and Vaidya Nathan Applied Physics Letters 90, 233513-- June 4, 2007 ...[Visit Journal] Effective surface passivation of Type-II InAs/GaSb superlattice photodiodes with cutoff wavelengths in the long-wavelength infrared is presented. A stable passivation layer, the electrical properties of which do not change as a function of the ambient environment nor time, has been prepared by a solvent-based surface preparation, vacuum desorption, and the application of an insulating polyimide layer. Passivated photodiodes, with dimensions ranging from 400×400 to 25×25 µm², with a cutoff wavelength of ~11 µm, exhibited near bulk-limited R₀A values of ~12 Ω·cm², surface resistivities in excess of 10⁴ Ω·cm, and very uniform current-voltage behavior at 77 K. [reprint (PDF)]
12.	Recent advances in III-Nitride materials, characterization and device applications M. Razeghi, X. Zhang, P. Kung, A. Saxler, D. Walker, K.Y. Lim, and K.S. Kim SPIE Conference: Solid State Crystals in Optoelectronics and Semiconductor Technology; Proceedings 3179-- October 7, 1996 ...[Visit Journal] High-quality AlN, GaN, AlGaN have been grown on sapphire substrate by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The x-ray rocking curve of AlN and GaN were 100 arcsecs and 30 arcsecs respectively with Pendelloesung oscillations, which are the best reported to date. GaN with high crystallinity simultaneously exhibited high optical and electrical quality. Photoluminescence linewidth of GaN at 77K was as low as 17 meV, which is the best reported to date. Si-doped GaN had a mobility higher than 300 cm²/V·s. GaN has been also successfully grown on LiGaO₂ substrate with LP-MOCVD for the first time. AlGaN for the entire composition range has been grown. These layers exhibited the lowest x-ray FWHM reported to date. The excellent optical quality of these layers have been characterized by room temperature UV transmission and photoluminescence. N-type doping of AlGaN with Si has ben achieved up to 60 percent Al with mobility as high as 78 cm²/V·s. Al_xGa_1-xN/Al_yGa_1-yN superlattice with atomically sharp interface have been demonstrated. Optically-pumped stimulated emission in GaN:Ge and GaN:Si has been observed with threshold optical power density as low as 0.4 MW/cm². AlGaN photoconductors with cut-off wavelengths from 200 nm to 365 nm have been achieved for the first time. GaN p-n junction photovoltaic detector with very selective photoresponse have been demonstrated and theoretically modeled. Ti/AlN/Si metal-insulator- semiconductor capacitor with high capacitance-voltage performances at both low and high frequencies and low interface trap level density have been demonstrated for the first time in this material system. [reprint (PDF)]
12.	High Power 0.98 μm GaInAs/GaAs/GaInP Multiple Quantum Well Laser K. Mobarhan, M. Razeghi, G. Marquebielle and E. Vassilaki Journal of Applied Physics 72 (9)-- November 1, 1992 ...[Visit Journal] We report the fabrication of high quality Ga_0.8In_0.2As/GaAs/Ga_0.51In_0.49P multiple quantum well laser emitting at 0.98 μm grown by low pressure metalorganic chemical vapor deposition. Continuous wave operation with output power of 500 mW per facet was achieved at room temperature for a broad area laser with 130 μm width and 300 μm cavity length. This is an unusually high value of output power for this wavelength laser in this material system. The differential quantum efficiency exceeded 75% with excellent homogeneity and uniformity. The characteristic temperature, T₀ was in the range of 120–130 K. [reprint (PDF)]
12.	High power asymmetrical InAsSb/InAsSbP/AlAsSb double heterostructure lasers emitting at 3.4 μm D. Wu, B. Lane, H. Mohseni, J. Diaz and M. Razeghi Applied Physics Letters 74 (9)-- March 1, 1999 ...[Visit Journal] Midinfrared lasers with an asymmetrical InPAsSb/InAsSb/AlAsSb double heterostructure are reported. Using the asymmetrical double heterostructure, p- and n-cladding layers are separately optimized; high energy-gap AlAsSb (Eg ≈ 1.5 eV) for the p-type cladding layer to reduce the leakage current, and thus to increase To, and low energy-gap InPAsSb (Eg ≈ 0.5 eV) for the n-cladding layer to have low turn-on voltage. 100-μm-width broad-area lasers with 1000 μm cavity length exhibited peak output powers of 1.88 W in pulse and 350 mW in continuous wave modes per two facets at T=80 K with To of 54 K and turn-on voltage of 0.36 V. Maximum peak output powers up to 6.7 W were obtained from a laser bar of total aperture of 400 μm width and cavity length of 1000 μm, with a differential efficiency of 34% and far-field beam divergence narrower than 40° at 80 K. [reprint (PDF)]
12.	Wafer-scale epitaxial lift-off of optoelectronic grade GaN from a GaN substrate using a sacrificial ZnO interlayer Akhil Rajan, David J Rogers, Cuong Ton-That, Liangchen Zhu, Matthew R Phillips, Suresh Sundaram, Simon Gautier, Tarik Moudakir, Youssef El-Gmili, Abdallah Ougazzaden, Vinod E Sandana, Ferechteh H Teherani, Philippe Bove, Kevin A Prior, Zakaria Djebbour, Ryan McClintock and Manijeh Razeghi Journal of Physics D: Applied Physics, Volume 49, Number 31 -- July 15, 2016 ...[Visit Journal] Full 2 inch GaN epilayers were lifted off GaN and c-sapphire substrates by preferential chemical dissolution of sacrificial ZnO underlayers. Modification of the standard epitaxial lift-off (ELO) process by supporting the wax host with a glass substrate proved key in enabling full wafer scale-up. Scanning electron microscopy and x-ray diffraction confirmed that intact epitaxial GaN had been transferred to the glass host. Depth-resolved cathodoluminescence (CL) analysis of the bottom surface of the lifted-off GaN layer revealed strong near-band-edge (3.33 eV) emission indicating a superior optical quality for the GaN which was lifted off the GaN substrate. This modified ELO approach demonstrates that previous theories proposing that wax host curling was necessary to keep the ELO etch channel open do not apply to the GaN/ZnO system. The unprecedented full wafer transfer of epitaxial GaN to an alternative support by ELO offers the perspective of accelerating industrial adoption of the expensive GaN substrate through cost-reducing recycling. [reprint (PDF)]
12.	Temperature dependent characteristics of λ ~ 3.8 µm room-temperature continuous-wave quantum-cascade lasers J.S. Yu, A. Evans, S. Slivken, S.R. Darvish and M. Razeghi Applied Physics Letters, 88 (25)-- June 19, 2006 ...[Visit Journal] The highest-performance device displays pulsed laser action at wavelengths between 3.4 and 3.6 μm, for temperatures up to 300 K, with a low temperature (80 K) threshold current density of approximately 2.6 kA/cm², and a characteristic temperature of T₀~130 K. The shortest wavelength QCL (λ ~ 3.05 μm) has a higher threshold current density (~12 kA/cm² at T=20 K) and operates in pulsed mode at temperatures up to 110 K. [reprint (PDF)]
12.	Type-II InAs/GaSb Superlattice Focal Plane Arrays for High-Performance Third Generation Infrared Imaging and Free-Space Communication M. Razeghi, A. Hood and A. Evans SPIE Conference, January 25-29, 2007, San Jose, CA Proceedings – Optoelectronic Integrated Circuits IX, Vol. 6476, p. 64760Q-1-9-- January 29, 2007 ...[Visit Journal] Free-space optical communications has recently been touted as a solution to the "last mile" bottleneck of high speed data networks providing highly secure, short to long range, and high bandwidth connections. However, commercial near infrared systems experience atmospheric scattering losses and scintillation effects which can adversely affect a link's uptime. By moving the operating wavelength into the mid or long wavelength infrared enhanced link uptimes and increased range can be achieved due to less susceptibility atmospheric affects. The combination of room temperature, continuous wave' high power quantum cascade lasers and high operating temperature Type-II superlattice photodetectors offers the benefits of mid and long wavelength infrared systems as well as practical operating conditions. [reprint (PDF)]
12.	On the interface properties of ZnO/Si electroluminescent diodes J.L. Pau, J. Piqueras, D.J. Rogers, F. Hosseini Teherani, K. Minder, R. McClintock, and M. Razeghi Journal of Applied Physics, Vol. 107, No. 3, p. 033719-1-- February 1, 2010 ...[Visit Journal] ZnO layers grown on n⁻–Si(100), n⁺–Si(100), and n^––Si(111) substrates by pulsed-laser deposition were found to give electroluminescence. Light emission was observed in the form of discrete spots for currents over 1 mA with a white appearance to the naked eye. The intensity of these spots showed an erratic behavior over time, appearing and disappearing at random, while showing an associated random telegraph noise in the current signal. Regardless the substrate used, the electroluminescence spectra had a main broadband emission centered at about 600 nm and a relatively small peak at around 380 nm which corresponds to the energy of ZnO near band edge emission. Furthermore, the devices exhibited rectifying characteristics, whose current blocking direction depended on the substrate orientation. Optimization of ZnO conductivity and performing sample growth in N₂ ambient were found to be critical to enhance the emission intensity. Rutherford backscattering characterization revealed the existence of an intermixed region at the interface between ZnO and Si. To study the electronic properties at the interface, frequency dependent capacitance measurements were carried out. The junction capacitance became frequency dependent at the bias voltages at which light emission occurs due to the relatively slow trapping and generation processes at deep centers. These centers are believed to play an important role in the mechanism of light emission. [reprint (PDF)]
12.	AlGaN/AlN MOVPE heteroepitaxy: pulsed co-doping SiH4 and TMIn Ilkay Demir, Yusuf Koçak, A. Emre Kasapoğlu, Manijeh Razeghi, Emre Gür and Sezai Elagoz Semicond. Sci. Technol. 34 075028-- June 24, 2019 ...[Visit Journal] We report a new growth approach pulsed co-doping growth of Al_xGa_1−xN (x > 0.5) epilayers on AlN/Al₂O₃ templates by metal organic vapor phase epitaxy (MOVPE). Using this approach SiH₄ (silane) and TMIn (trimethylindium) supplied to the growth chamber alternately and pulsed during the growth of AlGaN epilayers. Structural and morphological quality of AlGaN epilayers were investigated by high resolution x-ray diffraction (HR-XRD), atomic force microscopy (AFM), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. It has shown that higher crystalline quality with low full width at half maximum (FWHM) and smoother surface morphology with reduced hexagonal hillock density has been obtained by the pulsed co-doping growth approach. Volcano like hillock structures has been confirmed by Raman mapping. [reprint (PDF)]
12.	Miniaturization: enabling technology for the new millennium M. Razeghi and H. Mohseni SPIE International Conference on Solid State Crystals, Zakopane, Poland, -- April 1, 2001 ...[Visit Journal] The history of semiconductor devices has been characterized by a constant drive toward lower dimensions in order to increase integration density, system functionality and performance. However, this is still far from being comparable with the performance of natural systems such as human brain. The challenges facing semiconductor technologies in the millennium will be to move toward miniaturization. The influence of this trend on the quantum sensing of infrared radiation is one example that is elaborated here. A new generation of infrared detectors has been developed by growing layers of different semiconductors with nanometer thicknesses. The resulted badgap engineered semiconductor has superior performance compared to the bulk material. To enhance this technology further, we plan to move from quantum wells to quantum wire and quantum dots. [reprint (PDF)]
12.	Generalized k·p perturbation theory for atomic-scale superlattices H. Yi and M. Razeghi Physical Review B 56 (7)-- August 15, 1997 ...[Visit Journal] We present a generalized k⋅p perturbation method that is applicable for atomic-scale superlattices. The present model is in good quantitative agreement with full band theories with local-density approximation, and approaches results of the conventional k⋅p perturbation method (i.e., Kane’s Hamiltonian) with the envelope function approximation for superlattices with large periods. The indirect band gap of AlAs/GaAs superlattices with short periods observed in experiments is explained using this method. [reprint (PDF)]
12.	InAsSb/InAsP strained-layer superlattice injection lasers operating at 4.0 μm grown by metal-organic chemical vapor deposition B. Lane, Z. Wu, A. Stein, J. Diaz, and M. Razeghi Applied Physics Letters 74 (23)-- June 7, 1999 ...[Visit Journal] We report high power mid-infrared electrical injection operation of laser diodes based on InAsSb/InAsP strained-layer superlattices grown on InAs substrate by metal-organic chemical vapor deposition. The broad-area laser diodes with 100 μm aperture and 1800 μm cavity length demonstrate peak output powers of 546 and 94 mW in pulsed and cw operation respectively at 100 K with a threshold current density as low as 100 A/cm². [reprint (PDF)]
12.	InTlSb alloys for infrared detection E. Bigan, Y.H. Choi, G. Labeyrie, and M. Razeghi Proceedings, SPIE Nonlinear Optics for High-Speed Electronics and Optical Frequency Conversion, Vol. 2145-- January 24, 1994 ...[Visit Journal] InTISb alloys have been grown by low-pressure metalorganic chemical vapor deposition, and characterized. Photoconductors exhibit a cutoff wavelength that can be tailored from 5.5 μm up to 9 μm by varying the thallium content. Experimental observations suggest that this can be further extended by increasing the thallium content. An InTISb photoconductor having a 9 μm cutoff wavelength exhibited a D* of 10⁹ cm·Hz^½·W^-1 at 7 μm operating wavelength. [reprint (PDF)]
12.	Energy harvesting from millimetric ZnO single wire piezo-generators Rogers, D. J.; Carroll, C.; Bove, P.; Sandana, V. E.; Goubert, L.; Largeteau, A.; Teherani, F. Hosseini; Demazeau, G.; McClintock, R.; Drouhin, H.-J.; Razeghi, M. Oxide-based Materials and Devices III. Edited by Teherani, Ferechteh H.; Look, David C.; Rogers, David J. Proceedings of the SPIE, Volume 8263, article id. 82631X, 7 pp. (2012).-- February 9, 2013 ...[Visit Journal] This work reports on investigations into the possibility of harvesting energy from the piezoelectric response of millimetric ZnO rods to movement. SEM & PL studies of hydrothermally grown ZnO rods revealed sizes ranging from 1 - 3 mm x 100 - 400 microns and suggested that each was a wurtzite monocrystal. Studies of current & voltage responses as a function of time during bending with a probe arm gave responses coherent with those reported elsewhere in the literature for ZnO nanowires or micro-rod single wire generators. The larger scale of these rods provided some advantages over such nano- and microstructures in terms of contacting ease, signal level & robustness. [reprint (PDF)]
12.	Effect of the spin split-off band on optical absorption in p-type Ga1 xInxAsyP1-y quantum-well infrared detectors J.R. Hoff, M. Razeghi and G. Brown Physical Review B 54 (15)-- October 15, 1996 ...[Visit Journal] Experimental investigations of p-type Ga_1-xIn_xAs_yP_1-y quantum-well intersubband photodetectors (QWIP’s) led to the discovery of unique features in photoresponse spectra of these devices. In particular, the strong 2–5 μm photoresponse of these QWIP’s was not anticipated based on previous experimental and theoretical results for p-type GaAs/Al_xGa_1-xAs QWIP’s. Our theoretical modeling of p-type QWIP’s based on the Ga_1-xIn_xAs_yP_1-y system revealed that the intense short-wavelength photoresponse was due to a much stronger coupling to the spin-orbit split-off components in the continuum than occurs for GaAs/Al_xGa_1-xAs QWIP’s. Due to the strong influence of the spin split-off band, an eight-band Kane Hamiltonian was required to accurately model the measured photoresponse spectra. This theoretical model is first applied to a standard p-type GaAs/Al_0.3Ga_0.7As QWIP, and then to a series of GaAs/Ga_0.51In_0.49P, GaAs/Ga_0.62In_0.38As_0.22P_0.78, Ga_0.79In_0.21As_0.59P_0.41/Ga_0.51In_0.49P, and Ga_0.79In_0.21As_0.59P_0.41/Ga_0.62In_0.38As_0.22P_0.78 QWIP’s. Through this analysis, the insignificance of spin split-off absorption in GaAs/Al_xGa_1-xAs QWIP’s is verified, as is the dual role of light-hole extended-state and spin split-off hole-extended-state absorption on the spectral shape of Ga_1-xIn_xAs_yP_1-y QWIP’s. [reprint (PDF)]
12.	Single-mode, high-power, midinfrared, quantum cascade laser phased arrays Wenjia Zhou , Donghai Wu , Quan-Yong Lu, Steven Slivken & Manijeh Razeghi Scientific Reports 8:14866-- October 5, 2018 ...[Visit Journal] We demonstrate single-mode, 16-channel, optical phased arrays based on quantum cascade laser technology, with emission wavelengths around 4.8 μm. The integrated device consists of a distributed feedback seed section, a highly-efficient tree array multi-mode interferometer power splitter, and a 16-channel amplifier array with a 4° angled facet termination. With a single layer Y₂O₃ coating, the angled facet reflectivity is estimated to be less than 0.1% for suppressing amplifier self-lasing. A peak output power of 30 W is achieved with an emission spectrum narrower than 11 nm and a side mode suppression ratio over 25 dB. Far field distribution measurement result indicates a uniform phase distribution across the array output. Using the same phased array architecture, we also demonstrate single-mode 3.8 μm QCL amplifier arrays with up to 20 W output power. [reprint (PDF)]
12.	Stranski-Krastanov growth of InGaN quantum dots emitting in green spectra C. Bayram and M. Razeghi Applied Physics A: Materials Science and Processing, Vol. 96, No. 2, p. 403-408-- August 1, 2009 ...[Visit Journal] Self-assembled InGaN quantum dots (QDs) were grown on GaN templates by metalorganic chemical vapor deposition. 2D–3D growth mode transition through Stranski–Krastanov mode was observed via atomic force microscopy. The critical thickness for In_0.67Ga_0.33N QDs was determined to be four monolayers. The effects of growth temperature, deposition thickness, and V/III ratio on QD formation were examined. The capping of InGaN QDs with GaN was analyzed. Optimized InGaN quantum dots emitted in green spectra at room temperature. [reprint (PDF)]
12.	Roadmap of Semiconductor Infrared Lasers and Detectors for the 21st Century M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] Since the first discovery, semiconductor infrared lasers and detectors have found many various applications in military, communications, medical, and industry sections. In this paper, the current status of semiconductor infrared lasers and detectors will be reviewed. Advantages and disadvantages of different methods and techniques is discussed later. Some basic physical limitations of current technology are studied and the direction to overcome these problems will be suggested. [reprint (PDF)]
12.	Chemical lift-off and direct wafer bonding of GaN/InGaN P-I-N structures grown on ZnO K. Pantzas, D.J. Rogers, P. Bove, V.E. Sandana, F.H. Teherani, Y. El Gmili, M. Molinari, G. Patriarche, L. Largeau, O. Mauguin, S. Suresh, P.L. Voss, M. Razeghi, A. Ougazzaden Journal of Crystal Growth, Volume 435, Pages 105-109-- November 7, 2015 ...[Visit Journal] p-GaN/i-InGaN/n-GaN (PIN) structures were grown epitaxially on ZnO-buffered c-sapphire substrates by metal organic vapor phase epitaxy using the industry standard ammonia precursor for nitrogen. Scanning electron microscopy revealed continuous layers with a smooth interface between GaN and ZnO and no evidence of ZnO back-etching. Energy Dispersive X-ray Spectroscopy revealed a peak indium content of just under 5at% in the active layers. The PIN structure was lifted off the sapphire by selectively etching away the ZnO buffer in an acid and then direct bonded onto a glass substrate. Detailed high resolution transmission electron microscopy and grazing incidence X-ray diffraction studies revealed that the structural quality of the PIN structures was preserved during the transfer process. [reprint (PDF)]
12.	High-power laser diodes based on InGaAsP alloys M. Razeghi Nature, Vol.369, p.631-633-- June 23, 1994 ...[Visit Journal] HIGH-POWER, high-coherence solid-state lasers, based on dielectric materials such as ruby or Nd:YAG (yttrium aluminium garnet), have many civilian and military applications. The active media in these lasers are insulating, and must therefore be excited (or ‘pumped’) by optical, rather than electrical, means. Conventional gas-discharge lamps can be used as the pumping source, but semiconductor diode lasers are more efficient, as their wavelength can be tailored to match the absorption properties of the lasing material. Semiconducting AlGaAs alloys are widely used for this purpose, but oxidation of the aluminium and the spreading of defects during device operation limit the lifetime of the diodes3, and hence the reliability of the system as a whole. Aluminium-free InGaAsP compounds, on the other hand, do not have these lifetime-limiting properties. We report here the fabrication of high-power lasers based on InGaAsP (lattice-matched to GaAs substrates), which operate over the same wavelength range as conventional AlGaAs laser diodes and show significantly improved reliability. The other optical and electrical properties of these diodes are either comparable or superior to those of the AlGaAs system. [reprint (PDF)]
12.	Tunability of intersubband absorption from 4.5 to 5.3 µm in a GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition N. Péré-Laperne, C. Bayram, L. Nguyen-Thê, R. McClintock, and M. Razeghi Applied Physics Letters, Vol. 95, No. 13, p. 131109-- September 28, 2009 ...[Visit Journal] Intersubband (ISB) absorption at wavelengths as long as 5.3 µm is realized in GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition. By employing low aluminum content Al_0.2Ga_0.8N barriers and varying the well width from 2.6 to 5.1 nm, ISB absorption has been tuned from 4.5 to 5.3 µm. Theoretical ISB absorption and interband emission models are developed and compared to the experimental results. The effects of band offsets and the piezoelectric fields on these superlattices are investigated. [reprint (PDF)]
12.	Surface leakage reduction in narrow band gap type-II antimonide-based superlattice photodiodes E.K. Huang, D. Hoffman, B.M. Nguyen, P.Y. Delaunay and M. Razeghi Applied Physics Letters, Vol. 94, No. 5, p. 053506-1-- February 2, 2009 ...[Visit Journal] Inductively coupled plasma (ICP) dry etching rendered structural and electrical enhancements on type-II antimonide-based superlattices compared to those delineated by electron cyclotron resonance (ECR) with a regenerative chemical wet etch. The surface resistivity of 4×10⁵ Ω·cm is evidence of the surface quality achieved with ICP etching and polyimide passivation. By only modifying the etching technique in the fabrication steps, the ICP-etched devices with a 9.3 µm cutoff wavelength revealed a diffusion-limited dark current density of 4.1×10⁻⁶ A/cm² and a maximum differential resistance at zero bias in excess of 5300 Ω·cm² at 77 K, which are an order of magnitude better in comparison to the ECR-etched devices. [reprint (PDF)]

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