Center for Quantum Devices - Most Downloaded Journal Articles

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16.	Structural, Optical, Electrical and Morphological Study of Transparent p-NiO/n-ZnO Heterojunctions Grown by PLD V. E. Sandana, D. J. Rogers, F. Hosseini Teherani, P. Bove, N. Ben Sedrine, M. R. Correia, T. Monteiro, R. McClintock, and M. Razeghi Proc. SPIE 9364, Oxide-based Materials and Devices VI, 93641O-- March 24, 2015 ...[Visit Journal] NiO/ZnO heterostructures were fabricated on FTO/glass and bulk hydrothermal ZnO substrates by pulsed laser deposition. X-Ray diffraction and Room Temperature (RT) Raman studies were consistent with the formation of (0002) oriented wurtzite ZnO and (111) oriented fcc NiO. RT optical transmission studies revealed bandgap energy values of ~3.70 eV and ~3.30 eV for NiO and ZnO, respectively and more than 80% transmission for the whole ZnO/NiO/FTO/glass stack over the majority of the visible spectrum. Lateral p-n heterojunction mesas (~6mm x 6mm) were fabricated using a shadow mask during PLD growth. n-n and p-p measurements showed that Ti/Au contacting gave an Ohmic reponse for the NiO, ZnO and FTO. Both heterojunctions had rectifying I/V characteristics. The junction on FTO/glass gave forward bias currents (243mA at +10V) that were over 5 orders of magnitude higher than those for the junction formed on bulk ZnO. At ~ 10^-7 A (for 10V of reverse bias) the heterojunction leakage current was approximately two orders of magnitude lower on the bulk ZnO substrate than on FTO. Overall, the lateral p-NiO/n-ZnO/FTO/glass device proved far superior to that formed by growing p-NiO directly on the bulk n-ZnO substrate and gave a combination of electrical performance and visible wavelength transparency that could predispose it for use in various third generation transparent electronics applications. [reprint (PDF)]
16.	Characteristics of Self-Assembled InGaAs/InGaP Quantum Dot Mid-Infrared Photoconductive Detectors Grown by Low Pressure MOCVD S. Kim, M. Erdtmann, and M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] We report the first self-assembled InGaAs/InGaP quantum dot intersubband infrared photoconductive detectors (QDIPs) grown on semi-insulating GaAs substrate by low pressure metal organic chemical vapor deposition (MOCVD). The InGaAs quantum dots were constructed on an InGaP matrix as self assembling in Stranski-Krastanow growth mode in optimum growth conditions. The detector structure was prepared for single layer and multi-stacked quantum dots for active region. Normal incident photoconductive response was observed at a peak wavelength of 5.5 μm with a high responsivity of 130 mA/W, and a detectivity of 4.74 X 10⁷ cm·Hz^½/W at 77 K for multi-stack QDIP. Low temperature photoresponse of the single quantum dot photodetector was characterized. Peak response was obtained between 16 K and 60 K. The detailed dark current noise measurements were carried on single and multistack quantum dot infrared detectors. High photoconductive gain as 7.6 x 10³ biased at 0.5 V results in increasing the intersubband carrier relaxation time as two order of magnitude compared quantum well infrared photodetectors. [reprint (PDF)]
16.	Novel Sb-based Alloys for Uncooled Infrared Photodetector Applications M. Razeghi SPIE Conference, San Jose, CA, -- January 22, 2001 ...[Visit Journal] We report on the growth and characterization of InSbBi, InTlSb, InTlP, and the quaternary alloys for uncooled long- wavelength infrared photodetector applications. The layers were grown on InSb and GaAs substrates by low-pressure metalorganic chemical vapor deposition. The incorporation of Bi and Tl in InSb was investigated with high-resolution x-ray diffraction, energy dispersive x-ray analysis, and optical photoresponse measurements. We also demonstrate the photodetectors fabricated from the grown InSbBi and InTlSb alloys. InSb_0.96Bi_0.04 photoconductive detectors exhibited a responsivity of 3.2 V/W at 77 K. The estimated Johnson noise limited detectivityat 7 micrometers was 1.7 X 10⁸ cm·Hz^½/W at 77 K. A room temperature operating InSb_0.95Bi_0.05 photodetector was also demonstrated.Photoresponse up to 12 micrometers was achieved at 300 K. The responsivity and Johnson noise-limited detectivity at 10.6 μm were 1.9 mV/W and 1.2 X 10⁶ cm·Hz^½/W, respectively. Photoresponse up to 15 μm was achieved at 300 K from quaternary InTlAsSb and InBiAsSb alloys. [reprint (PDF)]
16.	New design strategies for multifunctional and inexpensive quantum cascade lasers Steven Slivken; Manijeh Razeghi Proc. SPIE 10926, Quantum Sensing and Nano Electronics and Photonics XVI, 1092611-- February 1, 2019 ...[Visit Journal] This manuscript describes some of the new advances in active mid-infrared photonic integrated circuits enabled by new quantum cascade laser technologies. This includes monolithic beam steering which was achieved via the integration of a widely tunable QCL and a tapered grating outcoupler. A record 17.9 degrees of steering with a low divergence beam (0.5 degrees) was achieved. In addition, the use of surface emitting architectures is proposed as a means to reduce the manufacturing cost of next-generation QCLs. A reflective outcoupler is demonstrated which can allow for stable surface emission from a quantum cascade laser and has potential for cost-effective wafer-scale manufacturing. This outcoupler is integrated with an amplified, electrically tunable laser architecture to demonstrate high power surface emission at a wavelength near 4.9 μm. Single mode peak power up to 6.7 W is demonstrated with >6 W available over a 90 cm⁻¹ (215 nm) spectral range. All of this is achieved while maintaining a high quality output beam, similar to a standard edge emitter. [reprint (PDF)]
16.	High power InAsSb/InPAsSb/InAs mid-infrared lasers A. Rybaltowski, Y. Xiao, D. Wu, B. Lane, H. Yi, H. Feng, J. Diaz, and M. Razeghi Applied Physics Letters 71 (17)-- October 27, 1997 ...[Visit Journal] We demonstrate high-power InAsSb/InPAsSb laser bars (λ ≈ 3.2 μm) consisting of three 100 μm-wide laser stripes of 700 μm cavity length, with peak output power up to 3 W at 90 K, and far-fields for the direction perpendicular to the junction as narrow as 12° full width half maximum. Spectra and far-field patterns of the laser bars are shown to have excellent characteristics for a wide range of operating conditions, suggesting the possibility of even higher light power emission with good beam quality. Joule heating is shown to be the major factor limiting higher power operation. [reprint (PDF)]
16.	Substrate removal for high quantum efficiency back side illuminated type-II InAs/GaSb photodetectors P.Y. Delaunay, B.M. Nguyen, D. Hoffman and M. Razeghi Applied Physics Letters, Vol. 91, No. 23, p. 231106-- December 3, 2007 ...[Visit Journal] A substrate removal technique using an InAsSb etch stop layer improves by a factor of 2 the quantum efficiency of back side illuminated type-II InAs/GaSb superlattice photodetectors. After etching of the GaSb substrate with a CrO₃ based solution, the quantum efficiency of the diodes presents Fabry-Pérot oscillations averaging at 56%. Due to the confinement of the infrared light inside the devices, the quantum efficiency for certain devices reaches 75% at 8.5 µm. The implementation of this new technique to a focal plane array resulted in a decrease of the integration time from 0.23 to 0.08 ms. [reprint (PDF)]
16.	Electrical Characterization of Al_xGa_1-xN for UV Photodetector Applications A. Saxler, M. Ahoujja, W.C. Mitchel, P. Kung, D. Walker, and M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] Ultraviolet photodetectors have many military and commercial applications. However, for many of these applications, the photodetectors must be solar blind. This means that the photodetectors must have a cutoff wavelength of less than about 270 nm. Semiconductor based devices would then need energy gaps of over 4.6 eV. In the Al_xGa_1-xN system, the aluminum mole fraction, x, required is over 40%. As the energy gap is increased, doping becomes much more difficult, especially p-type doping. This report is a study of the electrical properties of Al_xGa_1-xN to enable better control of the doping. Magnesium doped p-type Al_xGa_1-xN has been studied using high-temperature Hall effect measurements. The acceptor ionization energy has been found to increase substantially with the aluminum content. Short-period superlattices consisting of alternating layers of GaN:Mg and AlGaN:Mg were also grown by low-pressure organometallic vapor phase epitaxy. The electrical properties of these superlattices were measured as a function of temperature and compared to conventional AlGaN:Mg layers. It is shown that the optical absorption edge can be shifted to shorter wavelengths while lowering the acceptor ionization energy by using short- period superlattice structures instead of bulk-like AlGaN:Mg. Silicon doped n-type films have also been studied. [reprint (PDF)]
16.	Gas Source Molecular Beam Epitaxy Growth and Characterization of Ga_0.51In_0.49P/In_xGa_1-xAs/GaAs Modulation-doped Field-effect Transistor Structures C. Besikci, Y. Civan, S. Ozder, O. Sen, C. Jelen, S. Slivken, and M. Razeghi Semiconductor Science Technology 12-- January 1, 1997 ...[Visit Journal] Lattice-matched Ga_0.51In_0.49P/GaAs and strained Ga_0.51In_0.49P/In_xGa_1−xAs/GaAs (0.1 ≤ x ≤ 0.25) modulation-doped field-effect transistor structures were grown by gas source molecular beam epitaxy by using Si as dopant. Detailed electrical characterization results are presented. The Ga_0.5In_0.49P/In_0.25Ga_0.75As/GaAs sample yielded dark two-dimensional electron gas densities of 3.75 x 10¹² cm^-2 (300 K) and 2.3 x 10¹² cm^-2 (77 K) which are comparable to the highest sheet electron densities reported in AlGaAs/InGaAs/GaAs and InAlAs/InGaAs/InP modulation-doped heterostructures. Persistent photoconductivity was observed in the strained samples only. A 0.797 eV deep level has been detected in the undoped GaInP layers of the structures. Another level, with DLTS peak height dependent on the filling pulse width, has been detected at the interface of the strained samples. Based on the DLTS and Hall effect measurement results, this level, which seems to be the origin of persistent photoconductivity, can be attributed to the strain relaxation related defects. [reprint (PDF)]
16.	Recent Advances in Room Temperature, High-Power Terahertz Quantum Cascade Laser Sources Based on Difference-Frequency Generation Quanyong Lu and Manijeh Razeghi Photonics, 3, 42-- July 7, 2016 ...[Visit Journal] We present the current status of high-performance, compact, THz sources based on intracavity nonlinear frequency generation in mid-infrared quantum cascade lasers. Significant performance improvements of our THz sources in the power and wall plug efficiency are achieved by systematic optimizing the device’s active region, waveguide, and chip bonding strategy. High THz power up to 1.9 mW and 0.014 mW for pulsed mode and continuous wave operations at room temperature are demonstrated, respectively. Even higher power and efficiency are envisioned based on enhancements in outcoupling efficiency and mid-IR performance. Our compact THz device with high power and wide tuning range is highly suitable for imaging, sensing, spectroscopy, medical diagnosis, and many other applications. [reprint (PDF)]
16.	Comparison of Gain and Threshold Current Density for InGaAsP/GaAs λ = 808 nm) Lasers with Different Quantum-Well Thickness H.J. Yi, J. Diaz, I. Eliashevich, G. Lukas, S. Kim, D. Wu, M. Erdtmann, C. Jelen, S. Slivken, L.J. Wang, and M. Razeghi Journal of Applied Physics 79 (11)-- July 1, 1996 ...[Visit Journal] We investigated the quantum‐size effects of quantum well (QW) on gain and threshold current density for InGaAsP/GaAs (λ=808 nm) laser diodes. In this work, a comparison is made of lasers with different QW thickness while keeping the optical confinement factors constant. We found that the threshold current density and differential efficiency were not affected by narrowing the QW thickness. The theoretical model taking into account the mixing of the valence bands and momentum relaxation for InGaAsP/GaAs lasers with spontaneous emission (optically pumped) measurement shows that the absence of difference between these structures can be attributed to the high relaxation rate. [reprint (PDF)]
16.	Low-threshold and high power (~9.0 μm) quantum cascade lasers operating at room temperature A. Matlis, S. Slivken, A. Tahraoui, K.J. Luo, J. Diaz, Z. Wu, A. Rybaltowski, C. Jelen, and M. Razeghi Applied Physics Letters 77 (12)-- September 18, 2000 ...[Visit Journal] We report a low threshold current density and high power for λ ∼ 9 μm AlInAs/GaInAs quantum cascade lasers operating at room temperature. The threshold current density is 1.95 kA/cm² at 300 K and 0.61 kA/cm² at 80 K for 5 μs pulses at 200 Hz repetition rate. The peak output power is 700 mW at room temperature and 1.3 W at 80 K per two facets for cavity length is 3 mm with a stripe width of 20 μm. The characteristic temperature T₀ is 185 °C. The slope efficiency is 450 and 800 mW/A at 300 and 80 K, respectively. In continuous wave operation, the output power is more than 150 mW at 80 K and 25 mW at 140 K. This high performance was achieved by improving the material growth and processing technology. [reprint (PDF)]
16.	High Frequency Extended Short-Wavelength Infrared Heterojunction Photodetectors Based on InAs/GaSb/AlSb Type-II Superlattices Romain Chevallier, Abbas Haddadi, Ryan McClintock, Arash Dehzangi , Victor Lopez-Dominguez, Pedram Khalili Amiri, Manijeh Razeghi IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 54, NO. 6-- December 1, 2018 ...[Visit Journal] InAs/GaSb/AlSb type-II superlattice-based photodetectors, with 50% cut-off wavelength of 2.1 µm and a −3 dB cut-off frequency of 4.8 GHz, are demonstrated, for 10 µm diameter circular mesas under 15 V applied reverse bias. A study of the cut-off frequency with applied bias and mesa size was performed to evaluate some of the limiting factors of photodetectors high frequency performance. [reprint (PDF)]
16.	Graphene versus oxides for transparent electrode applications Sandana, V. E.; Rogers, D. J.; Teherani, F. Hosseini; Bove, P.; Razeghi, M. Proc. SPIE 8626, Oxide-based Materials and Devices IV, 862603 (March 18, 2013)-- March 18, 2013 ...[Visit Journal] Due to their combination of good electrical conductivity and optical transparency, Transparent Conducting Oxides (TCOs) are the most common choice as transparent electrodes for optoelectronics applications. In particular, devices, such as LEDs, LCDs, touch screens and solar cells typically employ indium tin oxide. However, indium has some significant drawbacks, including toxicity issues (which are hampering manufacturing), an increasing rarefication (due to a combination of relative scarcity and increasing demand [1]) and resulting price increases. Moreover, there is no satisfactory option at the moment for use as a p-type transparent contact. Thus alternative materials solutions are actively being sought. This review will compare the performance and perspectives of graphene with respect to TCOs for use in transparent conductor applications. [reprint (PDF)]
16.	Two-dimensional magnetophonon resonance in GaInAs-InP and GaInAs-AlInAs heterojunctions and superlattices J.C. Portal, G. Gregoris a b , M.A. Brummell , R.J. Nicholas, M. Razeghi, M.A. Di Forte-Poisson, K.Y. Cheng, A.Y. Cho J.C. Portal, G. Gregoris, M.A. Brummell, R.J. Nicholas, M. Razeghi, M.A. Di Forte-Poisson, K.Y. Cheng, A.Y. Cho, Two-dimensional magnetophonon resonance in GaInAs-InP and GaInAs-AlInAs heterojunctions and superlattices, Surface Science, Volume 142, Issues 1–3, 1984, Pages 368-374,-- July 1, 1984 ...[Visit Journal] We report the observation of magnetophonon resonance in GaInAs-InP heterojunctions and measurements of the temperature dependence of the oscillations. A single series of oscillations due to scattering by the “GaAs-like” mode of GaInAs is seen, in contrast to GaInAs-InP superlattices, where scattering from InP phonons is also observed, and GaInAs-AlInAs heterojunctions, where coupling to “InAs-like” modes only is seen. This behaviour is discussed in terms of long-range phonon interactions and interface phonons. [reprint (PDF)]
16.	Quantum Dot Intersubband Photodetectors C. Jelen, M. Erdtmann, S. Kim, and M. Razeghi SPIE Conference, San Jose, CA, -- January 22, 2001 ...[Visit Journal] Quantum dots are recognized as very promising candidates for the fabrication of intersubband photodetectors in the infrared spectral range. At present, material quality is making rapid progress and some devices have been demonstrated. Examples of mid-infrared quantum dot intersubband photodetectors are presented along with device design and data analysis. Nonetheless, the performance of these devices remains less than comparable quantum well intersubband photodetectors due to difficulties in controlling the quantum dot size and distribution during epitaxy. [reprint (PDF)]
16.	GalnAs AND GaInAsP MATERIALS GROWN BY LOW PRESSURE MOCVD FOR MICROWAVE AND OPTOELECTRONIC APPLICATIONS J.P. Duchemin, J.P. Hirtz, M. Razeghi, M. Bonnet , S.D. Hersee J.P. Duchemin, J.P. Hirtz, M. Razeghi, GaInAs and GaInAsP materials grown by low pressure MOCVD for microwave and optoelectronic applications, Journal of Crystal Growth, 55, 1, 1981, Pages 64-73,-- August 1, 1981 ...[Visit Journal] The low pressure MOCVD technique has been successfully used to grow GaInAsP, lattice-matched to InP, for the complete compositional range between InP (λ=0.91 μm) and the ternary compound Ga0.47In0.53As (λ=1.67 μm). By contrast to LPE growth it has been found that during the MOCVD growth of double heterostructures InP can be grown directly onto the ternary or quaternary with no disturbance of the active layer, i.e. there is no effect equivalent to “melt back”. The compositional grading on both sides of the active layer was measured by scanning Auger spectroscopy on bevelled samples. It was found that the graded regions were typically less than 100 Å wide for GaInAsP active layers and less than 50 Å wide for GaInAs active layers. Single layers of undoped GaInAs exhibited a typical mobility of 6700 cm2 V-1s-1 at 1.5×1017 cm-3. The compositional uniformity of the ternary layers was characterised by measurement of the photoluminescence wavelength at various points on a large sample. The wavelength varied by <3 nm over 95% of the area, which was approximately 8 cm2. Our early MOCVD grown GaInAsP/InP DH lasers exhibited high thresholds due to a poor interface between the p-InP and the active layer. However, recently fabricated broad area lasers emitting at 1.27 μm show an average threshold current density of 1.5 kA cm-2 with a T0 of between 70 to 80 K. Stripe geometry lasers have being fabricated from this material and CW operation has been obtained. [reprint (PDF)]
16.	Growth and characterization of InSbBi for long wavelength infrared photodetectors J.J. Lee, J.D. Kim, and M. Razeghi Applied Physics Letters 70 (24)-- June 16, 1997 ...[Visit Journal] The epitaxial growth of InSbBi ternary alloys by low-pressure metalorganic chemical vapor deposition is reported on. X-ray diffraction spectra showed well resolved peaks of InSbBi and InSb films. Bi incorporation was confirmed by energy dispersive x-ray analysis. Photoresponse spectrum up to 9.3 μm which corresponds to 0.13 eV energy band gap has been measured in a sample with Bi composition of 5.8 at.% at 77 K. Electron mobility at room temperature ranges from 44 100 to 4910 cm²/V·s as Bi composition increases. [reprint (PDF)]
16.	Angled cavity broad area quantum cascade lasers Y. Bai, S. Slivken, Q.Y. Lu, N. Bandyopadhyay, and M. Razeghi Applied Physics Letters, Vol. 100, Np. 8, p. 081106-1-- August 20, 2012 ...[Visit Journal] Angled cavity broad area quantum cascade lasers (QCLs) are investigated with surface gratingbased distributed feedback (DFB) mechanisms. It is found that an angled cavity incorporating a one dimensional DFB with grating lines parallel to the laser facet offers the simplest solution for single mode and diffraction limited emission in the facet normal direction. A room temperature single mode QCL with the highest output power for wavelengths longer than 10 micron is demonstrated. This structure could be applied to a wide range of laser structures for power scaling along with spectral and spatial beam control. [reprint (PDF)]
16.	Extended short wavelength infrared heterojunction phototransistors based on type II superlattices Arash Dehzangi , Ryan McClintock, Donghai Wu , Abbas Haddadi, Romain Chevallier , and Manijeh Razeghi Applied Physics Letters 114, 191109-- May 17, 2019 ...[Visit Journal] A two terminal extended short wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb on a GaSb substrate is designed, fabricated, and investigated. With the base thickness of 40 nm, the device exhibited a 100% cut-off wavelength of 2.3 λ at 300 K. The saturated peak responsivity value is 320.5 A/W at 300 K, under front-side illumination without any antireflection coating. A saturated optical gain of 245 at 300K was measured. At the same temperature, the device exhibited a collector dark current density (at unity optical gain) and a DC current gain of 7.8 X 10³ A/cm² and 1100, respectively. The device exhibited a saturated dark current shot noise limited specific detectivity of 4.9 X 10¹¹ cm·Hz^½/W at 300 K which remains constant over a broad range of wavelengths and applied biases. [reprint (PDF)]
16.	Elimination of surface leakage in gate controlled Type-II InAs/GaSb mid-infrared photodetectors G. Chen, B.-M. Nguyen, A.M. Hoang, E.K. Huang, S.R. Darvish, and M. Razeghi Applied Physics Letters, Vol. 99, No. 18, p. 183503-1-- October 31, 2011 ...[Visit Journal] The electrical performance of mid-infrared type-II superlattice M-barrier photodetectors is shown to be limited by surface leakage. By applying gate bias on the mesa sidewall surface, leakage current is significantly reduced. Qualitatively IV modeling shows diffusion-dominated behavior of dark current at temperatures greater than 120 K. At 110 K, the dark current of gated device is reduced by more than 2 orders of magnitude, reaching the measurement system noise floor. With a quantum efficiency of 48% in front side illumination configuration, a 4.7μm cut-off gated device attains a specific detectivity of 2.5 × 10¹⁴ cm·Hz^½·W^-1 at 110 K, which is 3.6 times higher than in ungated devices. [reprint (PDF)]
15.	Thermal characteristics and analysis of quantum cascade lasers for biochemical sensing applications J.S. Yu, H.K. Lee, S. Slivken, and M. Razeghi SPIE Proceedings, Biosensing II, San Diego, CA (August 2-6, 2009), Vol. 7397, p. 739705-1-- August 2, 2009 ...[Visit Journal] We studied the thermal characteristics and analysis of InGaAs/InAlAs quantum cascade lasers (QCLs) in terms of internal temperature distribution, heat flux, and thermal conductance from the heat transfer simulation. The heat source densities were obtained from threshold power densities measured experimentally for QCLs under room-temperature continuous-wave operation. The use of a thick electroplated Au around the laser ridges helps increase the heat removal from devices. The two-dimensional anisotropic heat dissipation model was used to analyze the thermal behaviors inside the device. The simulation results were also compared with those estimated from experimental data. [reprint (PDF)]
15.	Room temperature compact THz sources based on quantum cascade laser technology M. Razeghi; Q.Y. Lu; N. Bandyopadhyay; S. Slivken; Y. Bai Proc. SPIE 8846, Terahertz Emitters, Receivers, and Applications IV, 884602 (September 24, 2013)-- November 24, 2013 ...[Visit Journal] We present the high performance THz sources based on intracavity difference-frequency generation from mid-infrared quantum cascade lasers. Room temperature single-mode operation in a wide THz spectral range of 1-4.6 THz is demonstrated from our Čerenkov phase-matched THz sources with dual-period DFB gratings. High THz power up to 215 μW at 3.5 THz is demonstrated via epi-down mounting of our THz device. The rapid development renders this type of THz sources promising local oscillators for many astronomical and medical applications. [reprint (PDF)]
15.	Low irradiance background limited type-II superlattice MWIR M-barrier imager E.K. Huang, S. Abdollahi Pour, M.A. Hoang, A. Haddadi, M. Razeghi and M.Z. Tidrow OSA Optics Letters (OL), Vol. 37, No. 11, p. 2025-2027-- June 1, 2012 ...[Visit Journal] We report a type-II superlattice mid-wave infrared 320 × 256 imager at 81 K with the M-barrier design that achieved background limited performance (BLIP) and ∼99%operability. The 280 K blackbody’s photon irradiance was limited by an aperture and a band-pass filter from 3.6 μm to 3.8 μm resulting in a total flux of ∼5 × 10¹² ph·cm⁻²·s⁻¹. Under these low-light conditions, and consequently the use of a 13.5 ms integration time, the imager was observed to be BLIP thanks to a ∼5 pA dark current from the 27 μm wide pixels. The total noise was dominated by the photon flux and read-out circuit which gave the imager a noise equivalent input of ∼5 × 10¹⁰ ph·cm⁻²·s⁻¹ and temperature sensitivity of 9 mK with F∕2.3 optics. Excellent imagery obtained using a 1-point correction alludes to the array’s uniform responsivity. [reprint (PDF)]
15.	High performance InGaAs/InGaP quantum dot infrared photodetector achieved through doping level optimization S. Tsao, K. Mi, J. Szafraniec, W. Zhang, H. Lim, B. Movaghar, and M. Razeghi SPIE Conference, Jose, CA, Vol. 5732, pp. 334-- January 22, 2005 ...[Visit Journal] We report an InGaAs/InGaP/GaAs quantum dot infrared photodetector grown by metalorganic chemical vapor deposition with detectivity of 1.3x10¹¹ cm·Hz^½/W at 77K and 1.2x10¹⁰ ccm·Hz^½/W at 120K. Modeling of the Quantum dot energy levels showed us that increased photoresponse could be obtained by doping the quantum dots to 4 electrons per dot instead of the usual 2 electrons per dot. This happens because the primary photocurrent transition is from the first excited state to a higher excited state. Increasing the quantum doping in our device yielded significant responsivity improvement and much higher detectivity as a result. This paper discusses the performance of this higher doping device and compares it to our previously reported device with lower doping. [reprint (PDF)]
15.	Thin-Film Antimonide-Based Photodetectors Integrated on Si Yiyun Zhang , Member, IEEE, Abbas Haddadi, Member, IEEE, Romain Chevallier, Arash Dehzangi, Member, IEEE, and Manijeh Razeghi , Life Fellow, IEEE IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 54, NO. 2-- April 1, 2018 ...[Visit Journal] Monolithic integration of antimonide (Sb)-based compound semiconductors on Si is in high demand to enrich silicon photonics by extending the detection range to longer infrared wavelengths. In this paper, we have demonstrated the damage-free transfer of large-area (1×1 cm² ) narrow-bandgap Sb-based type-II superlattice (T2SL)-based thin-film materials onto a Si substrate using a combination of wafer-bonding and chemical epilayer release techniques. An array of Sb-based T2SL-based long-wavelength infrared (LWIR) photodetectors with diameters from 100 to 400 μm has been successfully fabricated using standard "top–down" processing technique. The transferred LWIR photodetectors exhibit a cut-off wavelength of λ 8.6 μm at 77 K. The dark current density of the transferred photodetectors under 200 mV applied bias at 77 K is as low as 5.7×10⁻⁴ A/cm² and the R×A reaches 66.3 Ω·cm², exhibiting no electrical degradation compared with reference samples on GaSb native substrate. The quantum efficiency and peak responsivity at 6.75 μm (@77 K, 200 mV) are 46.2% and 2.44 A/W, respectively. The specific detectivity (D^*) at 6.75 μm reaches as high as 1.6×10¹¹ cm·Hz^1/2/W under 200 mV bias at 77 K. Our method opens a reliable pathway to realize high performance and practical Sb-based optoelectronic devices on a Si platform. [reprint (PDF)]

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