Showing papers on "Heterojunction published in 1980"
TL;DR: In this article, the conduction band discontinuity ΔEc was found to be 0.248 eV, corresponding to about to 0.66 ΔEg rather than Dingle's commonly accepted value 0.85 Δ Eg, attributed to compositional grading during LPE growth.
Abstract: The Debye length smearing that occurs in C‐V profiling has precluded the use of C‐V profiling from an adjacent Schottky barrier to measure the magnitude of energy band discontinuities at barriers in isotype heterojunctions. It is observed, however, that in such a process both the number of the charge carriers and the moment of their distribution are conserved. This information permits the extraction of values for both the conduction band discontinuity ΔEc and any interface charge density. This technique and experimental results for an LPE‐grown n‐N GaAs‐Al0.3Ga0.7As heterojunction are described. We find ΔEc =0.248 eV, corresponding to about to 0.66ΔEg rather than Dingle’s commonly accepted value 0.85ΔEg . The difference is attributed to compositional grading during LPE growth.
355 citations
TL;DR: In this paper, it was shown that in multilayered heterojunction structures the effective impact ionisation rates for electrons and holes can be very different, even if they are the same in the basic bulk materials.
Abstract: Calculations are reported showing that in multilayered heterojunction structures the effective impact ionisation rates for electrons and holes can be very different, even if they are the same in the basic bulk materials. The reason for this is the difference in the band-edge discontinuities for electrons and holes and the lower phonon mean free path for holes in quantum well structures.
240 citations
IBM1
TL;DR: In this article, experimental results in InAs-GaSb superlattices are reviewed, focussing on the difference between this type of super-lattice and that of GaAsGa 1− x Al x As.
161 citations
TL;DR: In this article, NiSi2 and CoSi2 layers have been grown on crystalline silicon by molecular beam epitaxy (MBE) and shown to be highly crystalline films can be grown by either silicon-metal codeposition or by pure metal deposition on substrates heated to 550-800°C.
Abstract: Epitaxial NiSi2 and CoSi2 layers have been grown on crystalline silicon by molecular beam epitaxy (MBE) Stoichiometric, highly crystalline films can be grown by either silicon‐metal codeposition or by pure metal deposition on substrates heated to 550–800 °C Crystalline quality is relatively insensitive to deposition conditions Film smoothness is maximized by codeposition at temperatures near 600 °C Both silicides have been epitaxially overgrown with silicon producing a fully crystalline silicon/metal silicide/silicon heterostructure
147 citations
TL;DR: In this article, the temperature at which ZnO is deposited is found to be of crucial importance for the photovoltaic performance of the cells, and Maxima of the open-circuit voltage, the shortcircuit current, and the dark resistance are observed for deposition temperatures between 230 and 240°C.
139 citations
Patent•
31 Dec 1980
TL;DR: An improved thin-film, large area solar cell, and methods for forming the same, having a relatively high light-to-electrical energy conversion efficiency and characterized in that the cell comprises a p-n type heterojunction formed of: (i) a first semiconductor layer comprising a photovoltaic active material selected from the class of I-III-VI 2 chalcopyrite ternary materials which is vacuum deposited in a thin "composition-graded" layer ranging from on the order of about 2.5 microns to about 5.0 mic
Abstract: An improved thin-film, large area solar cell, and methods for forming the same, having a relatively high light-to-electrical energy conversion efficiency and characterized in that the cell comprises a p-n type heterojunction formed of: (i) a first semiconductor layer comprising a photovoltaic active material selected from the class of I-III-VI 2 chalcopyrite ternary materials which is vacuum deposited in a thin "composition-graded" layer ranging from on the order ot about 2.5 microns to about 5.0 microns (≅2.5 μm to ≅5.0 μm) and wherein the lower region of the photovoltaic active material preferably comprises a low resistivity region of p-type semiconductor material having a superimposed region of relatively high resistivity, transient n-type semiconductor material defining a transient p-n homojunction; and (ii), a second semiconductor layer comprising a low resistivity n-type semiconductor material; wherein interdiffusion (a) between the elemental constituents of the two discrete juxtaposed regions of the first semiconductor layer defining a transient p-n homojunction layer, and (b) between the transient n-type material in the first semiconductor layer and the second n-type semiconductor layer, causes the The Government has rights in this invention pursuant to Contract No. EG-77-C-01-4042, Subcontract No. XJ-9-8021-1 awarded by the U.S. Department of Energy.
119 citations
TL;DR: In this article, a thin film CdS/CdTe solar cells with an efficiency of 6.3 % have been prepared on a borosilicate glass substrate of 4s×4 cm2 by successively repeating screen printing and heating (sintering) of each paste.
Abstract: Thin film CdS/CdTe solar cells with an efficiency of 6.3 % have been prepared on a borosilicate glass substrate of 4s×4 cm2 by successively repeating screen printing and heating (sintering) of each paste of CdS, CdTe and C. The CdS paste consists of CdS, CdCl2, GaCl2 and propylene glycol (PG). The CdTe paste contains CdCl2 and PG, and the C paste contains PG and a small amount of acceptor impurity. During the heating of C paste, an nCdS/pCdTe heterojunction is formed. In the most efficient cell, the peak of electron voltaic effect exists within 1 µm of the CdTe side from the CdS/CdTe metallurgical boundary. The C electrode cell is more stable than the previous Cu2Te electrode cell for an accelerated life test. From 25 elemental cells with 4×4 cm2 substrate, a 1 watt module has tentatively been constructed with a module efficiency of 2.9 %.
116 citations
TL;DR: InGaAsP/InP buried heterostructure lasers with a stripe width of 1-2 μm have been fabricated by two-step liquid phase epitaxy and preferential chemical etching as discussed by the authors.
Abstract: InGaAsP/InP buried‐heterostructure lasers with a stripe width of 1–2 μm have been fabricated by two‐step liquid phase epitaxy and preferential chemical etching. They operate in the fundamental transverse mode at wavelengths of ∼1.3 μm with threshold current as low as 22 mA. The temperature limit for cw operation is 80 °C.
110 citations
TL;DR: In this article, it is argued that the atomic geometry at a (110) interface should be particularly favorable for defect-free heteroepitaxy in such systems, for two reasons: (a) Recent work by Harrison et al. has shown that interfaces other than (110)-interfaces must reconstruct Such reconstruction will be incomplete, leaving behind hard-to-control interface charges (b) The free surface reconstruction of the diamond surface is such that it should favor subsequent growth of zincblende structures without antiphase domain boundaries
Abstract: Recent successful (110) growth of GaAs on Ge has prompted a reevaluation of the (110) orientation for the MBE growth of zincblende‐on‐diamond–type heterostructures It is argued that the atomic geometry at a (110) interface should be particularly favorable for defect‐free heteroepitaxy in such systems, for two reasons: (a) Recent work by Harrison et al has shown that interfaces other than (110) interfaces in such systems must reconstruct Such reconstruction will be incomplete, leaving behind hard‐to‐control interface charges (b) The free‐surface reconstruction of the diamond‐structure (110) surface is such that it should favor subsequent growth of zincblende structures without antiphase domain boundaries
106 citations
TL;DR: In this paper, the threshold current density of quantum-well AlxGa1−xAs−GaAs heterostructure laser diodes, grown by MO•CVD, is shown to be less temperature dependent than that of conventional DH lasers.
Abstract: Data are presented showing that the threshold current density Jth(T) of quantum‐well AlxGa1−xAs‐GaAs heterostructure laser diodes, grown by MO‐CVD, is less temperature dependent than that of conventional DH lasers. T0 in the usual expression Jth∝exp(T/T0) can be high as 437 °C. This behavior is explained in terms of the steplike density of states and the disturbed electron and phonon distribution functions of the quantum‐well active region.
103 citations
TL;DR: In this article, the authors used molecular beam epitaxy to grow CuInSe2 layers on CdS (0001B) and other substrates at a substrate temperature of 300 °C.
Abstract: We have used molecular beam epitaxy to grow CuInSe2 layers on CdS (0001B) and other substrates. Epitaxial growth is obtained at a substrate temperature of 300 °C. The ratio of the arrival rates of copper to indium is the key parameter governing layer stoichiometry. In order to produce low‐resistivity p‐type layers, the Cu/In arrival rate ratio must be slightly higher than that used to grow nominally stoichiometric layers. This suggests that a different defect is controlling electrical properties, rather than the copper vacancy complex which dominates bulk material. We have fabricated CuInSe2/CdS heterojunctions which show a maximum solar conversion efficiency of ∼5%.
TL;DR: In this paper, the effects of low-energy ion bombardment on enhancing elemental diffusion rates at both heterojunction interfaces during film deposition and over the compositionally altered layer created during sputter etching alloy targets have been considered.
Abstract: The effects of low‐energy ion bombardment on enhancing elemental diffusion rates at both heterojunction interfaces during film deposition and over the compositionally altered layer created during sputter etching alloy targets have been considered. Depth dependent enhanced interdiffusion coefficients, expressed as D*(x)=D*(0) exp(−x/Ld), where D*(0) is more than five orders of magnitude greater than thermal diffusion values, were measured in InSb/GaSb multilayer structures deposited by multitarget bias sputering. D*(0) was determined from the amplitude u of the compositional modulation in the multilayered films (layer thicknesses between 20 and 45 A) as measured by superlattice x‐ray diffraction techniques. The value of D*(0) was found to increase from 3×10−17 to 1×10−16 cm2/sec as the applied substrate bias was increased from 0 to −75 V. However even at Va=0, the diffusion coefficient was enhanced owing to an induced substrate potential with respect to the positive space‐charge region in the Ar discharge....
TL;DR: In this paper, the threshold current density of a quantum-well laser diode is calculated taking into account the quasi-two-dimensional nature of the heterostructure and the step-like densities of states and the perturbed (hot) carrier distribution of a quasiprocessor.
Abstract: The threshold current density, Jth, of a quantum-well laser diode is calculated taking into account the quasi-two-dimensional nature of the heterostructure. The calculated value of Jth(T) for a quantum-well laser diode is found, in agreement with experiment, to be less temperature sensitive than that of a conventional double heterojunction laser. The step-like densities of states and the perturbed (hot) carrier distribution of a quasi-two-dimensional structure are responsible for the weaker temperature dependence. Supporting data on quantum-well AlxGa1-xAsGaAs heterostructure laser diodes grown by MO-CVD are presented showing that in the conventional expression Jth(T) = Jth(0) exp (T/T0), T0 can be as high as ∼ 437°C.
TL;DR: In this paper, a GaAlAs double-heterostructure laser was integrated with a heterojunction bipolar transistor on a GaAs substrate by means of a mutually compatible structure formed by Be ion implantation.
Abstract: A GaAlAs double-heterostructure laser has been monolithically integrated with a heterojunction bipolar transistor on a GaAs substrate. Integration is achieved by means of a mutually compatible structure formed by Be ion implantation. Typical pulsed threshold currents for the laser are 60 mA, and the transistors have a typical common-emitter current gain of 900.
TL;DR: In this paper, a simple substitution of binary (AlAs) for ternary (AlGaAs) barriers eliminates alloy clustering and its effects, and makes unambiguous the identification of clustering in alloy barriers.
Abstract: Data on spontaneous and stimulated emission, in the photon-energy range ${E}_{g}+5\ensuremath{\hbar}{\ensuremath{\omega}}_{\mathrm{LO}}\ensuremath{\gtrsim}\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\gtrsim}{E}_{g}$, are presented on ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$-GaAs quantum-well heterostructures with ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ ($x\ensuremath{\sim}0.4\ensuremath{-}0.5$) coupling barriers of size ${L}_{B}\ensuremath{\sim}40\ensuremath{-}70$ \AA{} and GaAs wells of size ${L}_{z}\ensuremath{\sim}30\ensuremath{-}40$ \AA{}. For ${L}_{z}$,${L}_{B}\ensuremath{\lesssim}50$ \AA{}, Al-Ga disorder (clustering) in the alloy barriers is consistent with the observed spectral broadening and downward energy shift of the confined-particle transitions. A simple substitution of binary (AlAs) for ternary (AlGaAs) barriers eliminates alloy clustering and its effects, and makes unambiguous the identification of clustering in alloy barriers.
TL;DR: In this article, the two-dimensional electron gas as high as 61 500 cm2/V sec, with a carrier concentration of 5.7×1011 cm−2, was obtained at 66 K in a selectively doped GaAs/n−AlGaAs heterojunction structure grown by molecular beam epitaxy.
Abstract: Mobility of the two‐dimensional electron gas as high as 61 500 cm2/V sec, with a carrier concentration of 5.7×1011 cm−2, was obtained at 66 K in a selectively doped GaAs/n‐AlGaAs heterojunction structure grown by molecular beam epitaxy. This mobility is a factor of 2–3 larger than any reported so far in similar structures.
TL;DR: In this article, a consistent account of the basic operation of the CdS/Cu2S solar cell as a heterojunction dominated by interface recombination is presented, and the model is in good agreement with the results seen in high efficiency cells and from it the increased open-circuit voltage seen in (CdZn)S/cu2S cells can be predicted.
Abstract: The Monte Carlo method has been used to simulate electron transport in GaAs/AlGaAs heterostructures with an electric field applied parallel to the heterojunction interface. The simulations indicate that a unique physical mechanism for negative differential conductivity is provided by such layered heterostructures, which is analogous in many respects to the Gunn effect. This mechanism has been termed ’’real‐space electron transfer’’ since it involves the transfer of electrons from a high‐mobility GaAs region to an adjacent low‐mobility AlGaAs region as the applied electric field intensity is increased. The simulations further indicate that the important details of the resulting velocity‐field characteristics for these layered heterostructures can be controlled primarily through material doping densities, layer thicknesses, and the material properties of the individual layers. Thus, the phenomenon of real‐space electron transfer potentially provides the ability to ’’engineer’’ those basic material propertie...
TL;DR: In this article, extensive data were presented on various photopumped multiple-quantum-well AlxGa1−x As-GaAs heterostructures, grown by metalorganic chemical vapor deposition, showing the variety of laser operation that can be observed one and two phonons below the lowest (n=1, n′=1′) confined-particle transitions.
Abstract: Extensive data are presented on various photopumped multiple‐quantum‐well AlxGa1−x As‐GaAs heterostructures, grown by metalorganic chemical vapor deposition, showing the variety of laser operation that can be observed one and two phonons below the lowest (n=1, n′=1′) confined‐particle electron‐to‐heavy‐hole (e→hh, n) and electron‐to‐light‐hole (e→lh, n′) recombination transitions. These experiments are performed on small cleaved rectangular samples that, because of two identifiable sets of orthogonal coupled modes, permit unambiguous identification of laser operation on LO‐phonon sidebands below the confined‐particle transitions. For a small number (two) of closely coupled (∼50 A) GaAs quantum wells of size Lz ∼50 A laser operation occurs on multiples of h/ωLO from one phonon below transition n=1 (E1) to within a phonon or two of the L indirect band edge. AlxGa1−x As‐GaAs heterostructures with more coupled GaAs quantum wells readily permit observation of laser operation two phonons below the lowest confined‐particle transitions. Besides the use of size to reduce carrier scattering to lower energies in a GaAs quantum well, high Zn doping is used to screen and reduce the electron‐phonon interaction and thus reduce the carrier scattering to lower energies. The strong phonon participation in the laser operation of these quantum‐well heterostructures, which are not superlattices, demonstrates that the electron‐phonon interaction observed in this work is a true two‐dimensional effect (and not, e.g., the effect of Brillouin‐zone folding). An analysis and arguments are presented justifying this statement and, in addition, leading to the important conclusion that stimulated phonon emission is possible and might play (or likely plays) a role in the quantum‐well heterostructures of this work.
TL;DR: In this paper, a 3×1 LEED pattern was observed on clean, cleaved GaAs(110) surfaces with a thickness of 100 monolayers at different growth temperatures.
Abstract: On clean, cleaved GaAs(110) surfaces Ge was deposited by MBE up to a thickness of 100 monolayers at different growth temperatures. At the interface Ge reacts with the GaAs. As measured by AES (0.65±0.25) monolayers of arsenic are dissolved and mainly segregated at the surface of the growing film. At a growth temperature of 295 °C the interface is abrupt, but broadened by diffusion for growth at 395 °C. With Ge films thicker than 5 monolayers a well developed 3×1 LEED pattern is observed which converts to a 2×1 pattern during an anneal above 400 °C. The LEED patterns are interpreted by surface segregation of GeAs2 and GeAs layers, respectively, one to two monolayers thick. The observed increase of the work function in the submonolayer coverage range is explained by band bending due to chemisorption induced surface states at Ess−Ev=0.89 eV and with a charge transfer of −(0.2±0.1) e0 per Ge atom. Therefore it is concluded that the Ge atoms bond to As atoms in the initial growth stage. The band scheme of the heterostructure is discussed, and the conduction band discontinuity of the Ge:GaAs(110) heterstructure is estimated as ΔEc?0.12) eV.
TL;DR: In this article, the first observation of a two-dimensional hole gas (2DHG) at a semiconductor heterojunction interface (GaAs/AlxGa1−xAs) was reported.
Abstract: We report the first observation of a two‐dimensional hole gas (2DHG) at a semiconductor heterojunction interface (GaAs/AlxGa1−xAs). Low‐temperature angular‐dependent Shubnikov‐de Haas measurements demonstrate the two dimensionality of the system and yield a carrier surface density of 7×1011 cm−2. From the temperature dependence of the magneto oscillations we derive an effective mass of 0.35±0.1m0 for the carriers. Hall measurements establish a He temperature mobility of μ≈1700 cm2/V sec.
TL;DR: In this paper, a method for the calculation of the electronic structure of interfaces is described and applied to the (100) Ge-GaAs and Ge-ZnSe heterojunctions, based on the Koster-Slater scattering-theoretic technique.
Abstract: A method for the calculation of the electronic structure of interfaces is described and applied to the (100) Ge-GaAs and Ge-ZnSe heterojunctions The method is based on the Koster-Slater scattering-theoretic technique The interface is described as a local perturbation of an unperturbed system consisting of two initially noninteracting, lattice-matched bulk solids The changes in their electronic structure due to the interface can be calculated very efficiently and accurately in terms of one-particle bulk Green's functions We present interface band structures and wave-vector-integrated as well as wave-vector-resolved local densities of states for the Ge-GaAs and the Ge-ZnSe interfaces All four interfaces give rise to essentially three interface bands in the valence-band region, those for Ge-ZnSe being more pronounced than those for Ge-GaAs We compare our results with a previous calculation for the (100) Ge-Ga interface and with experiment We conclude that stoichiometrically mixed interfaces are more likely to occur in nature than ideal (100) interfaces
TL;DR: InGaAsP-InP heterojunction phototransistors have been fabricated by liquid phase epitaxy as discussed by the authors and have optical gains greater than 100 for 1.26μm radiation.
Abstract: InGaAsP‐InP heterojunction phototransistors have been fabricated by liquid phase epitaxy. The phototransistors have optical gains greater than 100 for 1.26‐μm radiation. High internal current gains (≳300) have been achieved. Phototransistor relative spectral response has been measured for wavelengths in the range 0.7–1.5 μm.
TL;DR: In this paper, an analytical model for negative differential resistance (NDR) and switching in layered GaAs-AlxGa1−xAs heterostructures with a high electric field parallel to the interface is presented.
Abstract: Calculations are presented for negative differential resistance (NDR) and switching in layered GaAsAlxGa1−xAs heterostructures with a high electric field parallel to the interface. The mechanism is based on thermionic emission of hot electrons from the GaAs layers into the AlxGa1−xAs layers. An analytical model is obtained in the limit of relatively large layer widths (400 A or wider). The method of moments is employed to solve the Boltzmann equation, assuming a position-dependent electron temperature and Quasi-Fermi level in the AlxGa1−xAs layers, and a position-independent electron temperature and Quasi-Fermi level in the narrower GaAs layer. Thermal conduction of hot electrons from the GaAs layer into the AlxGa1−xAs layers is taken into account. The results of the calculations show that the threshold electric field for the onset of NDR and the peak-to-valley ratio can be controlled to a large extent by adjusting the mobility of the AlxGa1−xAs layer, the layer dimensions, and the potential barrier (Al mole fraction in the AlxGa1−xAs).
TL;DR: In this article, the authors give a qualitative description of semiconductor-semiconductor heterojunction solar cells and the two groups of heterojunctions of greatest economic potential, very highly efficient cells for concentrator applications and moderately efficient thin film cells for fiat plates, are described with examples.
Abstract: This paper gives a qualitative description of semiconductor-semiconductor heterojunction solar cells. The two groups of heterojunctions of greatest economic potential, very highly efficient cells for concentrator applications and moderately efficient thin film cells for fiat plates, are described with examples. These examples illustrate the role of heterojunctions in surface passivation, monolithic multijunction devices, devices with semiconductors of only one conductivity type and low-temperature fabrication techniques.
TL;DR: In this paper, a careful analysis of an abrupt heterojunction consisting of two distinct semiconductors either intrinsic or extrinsic is presented, taking into account all appropriate boundary conditions.
Abstract: A careful analysis of an abrupt heterojunction consisting of two distinct semiconductors either intrinsic or extrinsic is presented. The calculations apply to a one-dimensional, nondegenerate structure. Taking into account all appropriate boundary conditions, it is shown that the intrinsic Fermi level shows a discontinuity at the interface between the two materials which leads to a discontinuity of the valence band edge equal to the difference in the band gap energies of the two materials. The conduction band edge stays continuous however. This result is independent of possible charged interface states and in sharp contrast to the Anderson model. The reasons for this discrepancy are discussed.
Patent•
25 Aug 1980TL;DR: In this article, a very thin low refractive index and high bandgap may be employed between at least active layer and one intermediate layer or at least contiguous with a surface of at least one intermediary layer remote from the active layer.
Abstract: In a heterostructure injection laser having an active layer sandwiched by a pair of intermediate index layers, a very thin low refractive index and high bandgap may be employed between at least active layer and one intermediate layer or at least contiguous with a surface of at least one intermediate layer remote from the active layer. These thin layers may be applied in various positional combinations to produce desired effects on fundamental mode guiding.
TL;DR: In this article, the properties of indium-tin oxide (ITO)/CdTe junction solar cells prepared by rf sputtering of ITO on P-doped CdTe single-crystal substrates have been investigated through measurements of the electrical and photovoltaic properties.
Abstract: The properties of indium‐tin oxide (ITO)/CdTe junction solar cells prepared by rf sputtering of ITO on P‐doped CdTe single‐crystal substrates have been investigated through measurements of the electrical and photovoltaic properties of ITO/CdTe and In/CdTe junctions, and of electron beam induced currents (EBIC) in ITO/CdTe junctions. In addition, surface properties of CdTe related to the sputtering process were investigated as a function of sputter etching and thermal oxidation using the techniques of surface photovoltage and photoluminescence. ITO/CdTe cells prepared by this sputtering method consist of an n+‐ITO/n‐CdTe/p‐CdTe buried homojunction with about a 1‐μm‐thick n‐type CdTe layer formed by heating of the surface of the CdTe during sputtering. Solar efficiencies up to 8% have been observed with V0c=0.82 V and Jsc=14.5 mA/cm2. The chief degradation mechanism involves a decrease in V0c with a transformation of the buried homojunction structure to an actual ITO/CdTe heterojunction.
TL;DR: In this article, the authors showed that electrons spill over only into the underlying GaAs layer from the top AlxGa1-xAs layer, which is the first report that electrons can spill over from the GaAs layers to the top of the Al0.25Ga0.75As layer.
Abstract: Modulation doped Al0.25Ga0.75As-GaAs heterojunctions have been prepared by molecular beam epitaxy (m.b.e.). Al0.25Ga0.75As layers were doped with Si to a level of ~ 3 × 1017 cm-3, whereas the GaAs layers were either unintentionally doped, doped lightly n-type with Sn, or doped lightly p-type with Be. Heterojunction structures having single and multiple periods have shown enhanced mobility only with the AlxGa1-xAs layer at the surface and the GaAs layer underlying. These results represent the first report that electrons spill over only into the underlying GaAs layer from the top AlxGa1-xAs layer.
TL;DR: In this article, undoped single and multiple-quantum-well InP-Inl-xGaxPl-zAsz (x∼0.13, z∼ 0.29) heterostructures of uniform well (Lz∼150 A) and coupling barrier size (200-300A ) have been grown and examined in photolumi-nescence.
Abstract: By means of computer-controlled liquid-phase epitaxy (LPE), undoped single-and multiple-quantum-well InP-Inl-xGaxPl-zAsz (x∼0.13, z∼0.29) heterostructures of uniform well (Lz∼150 A) and coupling barrier size (200–300A ) have been grown and examined in photolumi-nescence. Undoped samples are used to eliminate problems with impurities and to make possible study of the fundamental properties of quaternary quantum-well heterostructures. For a single quaternary quantum-well heterostructure of small enough well size (Lz∼150A), which still collects holes but not electrons (electron scattering length >LZ), hot-electron (p2/2mn∼ΔEc) recombination from Ec(InP) to bound holes in the valence-band well (i.e., to Ev(InGaPAs)), leads to stimulated emission in a band ∼ 80 meV below Eg(InP) and thus to an estimate of Δ Ev∼ 80 meV (ΔEc∼2×ΔEv) for the InP-InGaPAs valence-band discontinuity. On rectangular samples of multiple quantum-well LPE InP-In1-xGaxP1-zAsz heterostructures laser operation has been identified on LO phonon sidebands located below the lowest confined-particle transitions. A 5-barrier, 6-well quaternary quantum-well heterostructure exhibits phonon-assisted laser operation shifted in energy below confined-particle transitions by an InGaAs-like phonon (¯hωL0∼31 meV) and for an 11-barrier, 12-well heterostructure shifted by an InP-like phonon (¯hωL0∼43 meV). The 11+12 quaternary quantum-well heterostructure is shown to be capable of operating as a room temperature continuous (CW, 300K) laser (¯hω