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Lead salt photoconductors are popular IR photodetectors due to their outstanding performance-to-cost ratio, high room temperature performance (D* > 1E10) and availability of large area detectors. The lead salt photodetector history has been reviewed also recognizing several more recent research developments. The chemical bath deposition technique for production of the lead salt detectors has been outlined, followed by a review of the basics for their characterization. Spectral responses of both PbS and PbSe detectors collected in a wide temperature range and properly corrected have been presented.

Fully converting the lead salt to perovskite is crucial for the performance of the perovskite solar cells via the sequential deposition method. By applying mixture of PbI2 and PbCl2 as the lead salts here, a fast conversion rate was found and a new PbICl phase was involved.

Mid-infrared vertical external cavity surface emitting lasers (VECSEL) were developed for the wavelength range 4 to 5 μm. The devices are based on lead salt materials grown by MBE on BaF2 or Si substrate. The VECSELs are optically pumped with a 1.55 μm wavelength laser. They are operating up to above room temperature. An output power 6 mWp was reached at a temperature of +27°C. The VECSELs are temperature tunable and lasing is observed from ∼4.8 μm at −60°C down to ∼4.2 μm at +40°C heat sink temperature.

Nanocrystals of PbTe synthesized by the reduction of tellurium powder with sodium borohydride (NaBH4) to produce telluride ions followed by a reaction with a lead salt. Considerable control of the reaction is possible when lead carbonate is used. Dots and rods of PbTe nanocrystals are obtained at different temperatures

A Lead salt midinfrared quantum-well (QW) laser on [110] orientation is proposed. Theoretical simulations of [110] QW edge-emitting lasers show a 70° temperature increase in continuous-wave operation compared to the conventional [100]-orientated lasers. This is because the gain on [100]-orientated QW structure is significantly increased. Among [100], [111], and [110] orientations, [110]-orientated QW structure offers the highest gain. PbSe∕PbSrSe QW structures were successfully grown on [110]-orientated BaF2 substrate by molecular-beam-epitaxy (MBE). Photoluminescence intensity of [110]-orientated samples was twice as high as that on [111]-orientated BaF2 substrates from the same MBE run.

A formalism for determining energy eigenstates of cylindrical lead salt quantum wires in the multiple-band envelope-function approximation is developed. Electron energy dispersion for quantum wire subbands within the conduction and valence bands is found.

Tunable mid‐infrared vertical external cavity surface emitting lasers were developed for the wavelength range around 3.8–3.9 μm and 3.2–3.3 μm, respectively. The devices are based on lead salt materials epitaxially grown by MBE on a Si substrate. The active part consists of PbSe QW in a PbSrSe host layer. Both devices are operated around −20 °C and have output power of several 10 mW. By changing the cavity length, a single mode hop free tuning range up to 80 cm−1 is achieved.

Optical stabilization of tunable lead-salt diode lasers (TDL) in the mid-infrared is presented for the first time. By introducing an external feedback mirror both the linewidth is substantially narrowed and the frequency of the TDL is stabilized and controlled via this mirror in a frequency-offset locked scheme. We achieved narrowing of the linewidth by 1–2 orders of magnitude or better. The TDL is offset-locked to a CO gas laser by a heterodyne technique: the beatnote between the two lasers is used to control the length of the external resonator. By this scheme we gain the capability of absolute frequency measurements with sub-Doppler accuracy. The improved spectral properties of the diode laser provide a new tool for high-resolution molecular spectroscopy in the mid-infrared.

Two-photon absorption (2PA) is measured for different sizes of lead-salt quantum dots, a slight increasing of the 2PA for smaller quantum-dots is observed and the results is discussed based on a four-band envelop function formalism.

We present the first mid-infrared VECSEL (Vertical External Cavity Surface Emitting Laser) for wavelengths above 3 μm. The structure is very simple: A 2 μm thick PbTe layer is embedded between two high reflectance mirrors and used as gain medium. It is optically pumped with a 1.5 μm wavelength laser. Emission is around 5 μm wavelength and output power up to > 40 mWp at 110K.

Several groups of narrow gap semiconductors have become particularly interesting in the fields of pure science and technology. Among these are some of the mercury, cadmium and lead compounds and some of the semimagnetic semiconductors. We report on the crystal growth of these materials and on the latest developments to meet the requirements of basic research and technology.

We report the synthesis and characterization of PbS quantum dot (QD) ionic liquids. Lead salt QDs have unique optical and electronic properties, which have potential applications in infrared light emitting devices and solar cells. Making them into ionic liquids does not degrade much of their optical properties, but makes them more stable in ambient conditions. © 2009 Materials Research Society.

A detailed study on microstructures in the form of pillars, rods and tubes based on IV-VI lead salt semiconductor structures grown in molecular beam epitaxy (MBE) was described. Several essential fabrication parameters that controlled the morphological aspects of those microstructures were clearly visualized. Tremendous enhancement of pulsed photoluminescence (PL) intensity was achieved from a single microrod or microtube compared to their bulk samples. The micropillar sample, having free-standing pillar diameter of 5 mum with an inter-pillar distance of 8 mum, showed a consistent temperature tunability of ~3.64 cm-1/0K of the pulsed PL emission peaks. All those novel results dictated a promising future of lead-salt based mid-infrared opto-electronics implemented mainly in the field of industrial trace gas-sensing.

A resonant-cavity enhanced detector operating in the mid-infrared at a wavelength around 3.6 micron is demonstrated. The device is based on a narrow-gap lead salt heterostructure grown by molecular beam epitaxy. Below 140 K, the photovoltage clearly shows a single narrow cavity resonance, with a relative line width of only 2 % at 80 K., Comment: 2 figures

Consider the mica bond used in rich resin mica-paper tapes of class F for main insulation in a large generator of high voltage. The results reveal that introducing bismaleimide into the curved system can improve the heat deflection temperature, the flexural strength at elevated temperature, and the dielectric properties. The cured system of epoxy resin-lead benzoylate has a high heat deflection temperature, but its dielectric properties at elevated temperature and heat aging life deteriorate. The combination of these two systems is well worth notice, if the amount of added lead salt is severely controlled. >

The development of low-cost uncooled thermal LWIR FPAs is resulting in the emergence of a new generation of infrared sensors for applications where affordability is the prerequisite for volume production. Both ferroelectric detector arrays and silicon-based microbolometers are finding numerous applications from gun sights to automotive FLIRs. There would be significant interest in a similar uncooled offering in the MWIR, but to date, thermal detectors have lacked sufficient sensitivity. The existing uncooled MWIR photon detector technology, based on polycrystalline lead salts, has been relegated to single-element detectors and relatively small linear arrays due to the high dark current and the stigma of being a 50-year-old technology.

Energy relaxation of an optically excited two-dimensional electron-hole gas has been investigated in PbSe as an example for dimensional quantization in a semiconductor with nearly symmetric valence and conduction band extrema. As compared with bulk-like reference samples the interband emission exhibits broadening and splitting into up to 5 clearly resolved lines. A systematic variation of the spectra with excitation density was observed: With increasing pump intensity the width of the total spectrum and the number of subbands increase due to both carrier heating and band filling. The emission bands are attributed to transitions between conduction and valence subbands with equal quantum number. Above a threshold well pronounced for each subband transition, the emission becomes stimulated. That indicates a potential for laser applications. >

Diode lasers made from IV–VI semiconductors emit in the MIR and are mainly used for high resolution spectroscopy with gas analysis as most important application. New developments driven by this use are described as well as potential new applications that in part do not depend on high spectral resolution.

With optical pumping, a lead salt vertical-cavity surface-emitting laser has been operated at wavelengths in the 4.50-4.60 mm range at temperatures up to T=289 K. For a 60 /spl mu/m/spl times/90 /spl mu/m pump spot, a device with a PbSe active region and Pb/sub 1-x/Sr/sub x/Se/BaF/sub 2/ quarter-wave mirror stacks was realised which had an unsaturated peak output power of 38 mW at 249 K.

Depot de chalcogenure de plomb sur KCl(100) et BaF 2 (111). Variation de l'epaisseur des couches et de leurs proprietes structurales et electriques en fonction des caracteristiques du faisceau laser, de la temperature du support et de la distance support-cible

Lead-salt diode lasers are useful for spectroscopic applications in the 2.5–30 μm wavelength range. These devices have previously required cryogenic cooling

The special properties of the lead chromate pigments have been used for many years in surface coatings. These properties which incude high opacity and brilliance of shade need not be further elaborated here. Naturally occurring lead chromate — the mineral crocoite — when powdered and formulated in a coatings composition will darken on exposure to light. Chrome pigments were once classified according to the composition of the lead salt used in manufacture. The principal classes were:—

Recently reported value of minority carrier lifetimes and time delays in lead salt diode lasers appear anomalous [A. Qadeer et al.: Appl. Phys. A33, 181–182 (1984)]. Two laser diodes, fabricated by the same technique (Hot Wall Epoxy) and of identical chemical constituents (PbSnTe and PbSnSe) failed to provide experimental evidence supporting these recently reported values, even when operated close to, but above the respective values of laser threshold current.

Figures of merit for lead sulfide (PbS) signal and noise are shown to be functions of resistance and time constant. It is found that the “signal proportional to resistance” rule-of-thumb is invalid. A criterion for choice of load resistance is presented.

The largest segment of postwar semiconductor research deals with the column-IV elements and their offspring, the III-V compounds. Just one column to the right, there is another closeknit family of nonmetals, the column-V semimetals As, Sb, and Bi, and the IV-VI semiconductor compounds. This review will focus on PbTe, SnTe, GeTe, and some of their alloys.1 Up until a few years ago, there would have been very little to say about the metal-semiconductor [M-SCI transition in these materials, since one of their distinctive properties has been the lack of extrinsic carrier freezeout. The discovery of deep-level defects and impurities in the IV-VI compounds has changed this situation completely, and has had a strong impact on many of their other basic properties. Currently, deep-level research generates about a third of all the papers published on the IV-VI family.

A brief review of the early development efforts in lead salt detectors is presented. Applications and methods of fabrication of contemporary devices are also discussed. State-of-the-art detectors are characterized for their chemical, structural, and photoelectronic properties. Performance characteristics as a function of operation temperature, frequency, background energy levels, etc., are described. Radiation effects are briefly discussed. A short summary of the mechanics of photoconductivity of the lead salt films is presented. Multi-element array designs and performance characteristics of typical current operational hardware are reviewed. Design and operational limitations are identified. Advanced concepts of Integrated (Hybrid and Monolithic) Detector Arrays are also reviewed.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Angular resolved photoemission spectra of PbS have been measured at T=300K and T = 20K in the energy range 18–100 eV. The purpose of this study was to understand the origin of indirect transitions previoulsy observed in the case of the lead salts. The spectra at low temperature show that indirect transitions dominate for 15