Center for Quantum Devices - Journal Articles and Conference Proceedings

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801.	Quantum hall effect and hopping conduction in InxGa1−xAs-InP heterojunctions at low temperature Y. Guldner, J.P. Hirtz, A. Briggs, J.P. Vieren, M. Voos, M. Razeghi Y. Guldner, J.P. Hirtz, A. Briggs, J.P. Vieren, M. Voos, M. Razeghi, Quantum hall effect and hopping conduction in InxGa1−xAs-InP heterojunctions at low temperature, Surface Science, Volume 142, Issues 1–3, 1984, Pages 179-181,-- July 1, 1984 We report investigations of the temperature dependence of the quantum Hall effect in modulation doped InxGa1−xAs-InP heterojunctions. The diagonal conductivity σxx is studied at several minima of the magneto-resistance ϱxx between 50 mK and 2 K. A hopping conduction mechanism is observed when the Fermi level is in the tail of the Landau levels. reprint
802.	High magnetic field studies of the two‐dimensional electron gas in GaInAs‐InP superlattices J. C. Portal; R. J. Nicholas; M. A. Brummell; M. Razeghi; M. A. Poisson J. C. Portal, R. J. Nicholas, M. A. Brummell, M. Razeghi, M. A. Poisson; High magnetic field studies of the two‐dimensional electron gas in GaInAs‐InP superlattices. Appl. Phys. Lett. 1 August 1983; 43 (3): 293–295.-- August 1, 1983 We report the observation of Shubnikov–de Haas oscillations in superlattices of GaInAs and InP, showing evidence of two‐dimensional behavior. The electron g‐factor is deduced from both the criteria for resolution of a spin splitting by comparison with the broadening parameter Γ, and from the tilted field method, and is shown to increase with increasing resolution of the Landau levels in a manner consistent with the theory of Ando and Uemura. In the ultraquantum limit, structure at ν=1/2 and ν=1/3 is observed. reprint
803.	Two-dimensional magnetophonon resonance. I. GaInAs-InP superlattices J C Portal, J Cisowski, R J Nicholas, M A Brummell, M Razeghi and M A Poisson J C Portal et al 1983 J. Phys. C: Solid State Phys. 16 L573-- April 5, 1983 Magnetophonon resonance results are reported for two-dimensional electron gases confined in the GaInAs layers of GaInAs-InP superlattices. Two series of oscillations are observed: one due to scattering by the 'GaAs-like' LO phonon mode of GaInAs, and the second due to interaction with InP LO phonons. The strength of the latter series increases relative to the former as the GaInAs layer thickness is reduced. This is evidence for a long-range phonon interaction, with the InP phonon field extending into the GaInAs to couple significantly with the electrons bound in the quantum wells. No evidence of interface phonons is seen. reprint
804.	Optical and crystallographic properties and impurity incorporation of GaxIn1−xAs grown by liquid phase epitaxy, vapor phase epitaxy, and metal organic chemical vapor deposition K.‐H. Goetz; D. Bimberg; H. Jürgensen; J. Selders; A. V. Solomonov; G. F. Glinskii; M. Razeghi K.‐H. Goetz, D. Bimberg, H. Jürgensen, J. Selders, A. V. Solomonov, G. F. Glinskii, M. Razeghi; Optical and crystallographic properties and impurity incorporation of GaxIn1−xAs (0.44-- March 29, 1983 Optical, crystallographic, and transport properties of nominally undoped n‐type and Zn doped p‐type Gax In1−xAs /InP (0.44 reprint
805.	Low pressure metalorganic chemical vapor deposition of InP and related compounds M. Razeghi, M. A. Poisson, J. P. Larivain & J. P. Duchemin Razeghi, M., Poisson, M.A., Larivain, J.P. et al. Low pressure metalorganic chemical vapor deposition of InP and related compounds. J. Electron. Mater. 12, 371–395 (1983). https://doi.org/10.1007/BF02651138-- March 1, 1983 The low pressure metalorganic chemical vapor deposition epitaxial growth and characterization of InP, Ga0.47In0.53 As and GaxIn1-xAsyP1-y, lattice-matched to InP substrate are described. The layers were found to have the same etch pit density (EPD) as the substrate. The best mobility obtained for InP was 5300 cm2 V−1S−1 at 300 K and 58 900 cm2 V−1 S−1 at 772K, and for GaInAs was 11900 cm2 V−1 S−1 at 300 K, 54 600 cm2 V−1 S−1 at 77 K and 90 000 cm V−1S−1 at 2°K. We report the first successful growth of a GaInAs-InP superlattice and the enhanced mobility of a two dimensional electron gas at a GaInAs -InP heterojunction grown by LP-MO CVD. LP MO CVD material has been used for GaInAsPInP, DH lasers emitting at 1.3 um and 1.5 um. These devices exhibit a low threshold current, a slightly higher than liquid phase epitaxy devices and a high differential quantum efficiency of 60%. Fundamental transverse mode oscillation has been achieved up to a power outpout of 10 mW. Threshold currents as low as 200 mA dc have been measured for devices with a stripe width of 9 um and a cavity length of 300 um for emission at 1.5 um. Values of T in the range 64–80 C have been obtained. Preliminary life testing has been carried out at room temperature on a few laser diodes (λ = 1.5μm). Operation at constant current for severalthousand hours has been achieved with no change in the threshold current. reprint
806.	Quantum oscillations at a Ga0.47In0.53AsInP heterojunction interface R.J Nicholas a, M.A Brummell a , J.C Portal b, M Razeghi c, M.A Poisson R.J Nicholas, M.A Brummell, J.C Portal, M Razeghi, M.A Poisson, Quantum oscillations at a Ga0.47In0.53AsInP heterojunction interface, Solid State Communications, Volume 43, Issue 11, 1982, Pages 825-828,-- September 1, 1982 We report the observation of a two dimensional gas of high mobility electrons at the interface of a Ga0.47In0.53AsInP heterojunction grown by MOCVD. The two dimensional electron concentrations and effective mass are determined by Shubnikov-de Haas studies, and compared with theoretical predictions. Evidence of an enhancement of the g-factor is observed. We also report observations of very pronounced quantum Hall steps as seen in GaAs-GaAlAs heterojunctions. reprint
807.	The quantum Hall effect in modulation doped In0.53Ga0.47As-InP heterojunctions Y. Guldner, J.P. Hirtz, J.P. Vieren, P. Voisin, M. Voos, M. Razeghi Y. Guldner, J.P. Hirtz, J.P. Vieren, P. Voisin, M. Voos, et al.. The quantum Hall effect in modulation doped In0.53Ga 0.47As-InP heterojunctions. Journal de Physique Lettres, 1982, 43 (16), pp.613-616. ff10.1051/jphyslet:019820043016061300ff. ffjpa-00232099f-- June 29, 1982 We report the first observation of the quantum Hall effect in modulation doped In0.53Ga0.47As-InP heterojunctions at 4.2 and 1.5 K. The results are then compared to data obtained in a GaAs-AlxGa1-xAs heterojunction having similar electronic characteristics.
808.	An accurate method to check chemical interfaces of epitaxial III‐V compounds R. Bisaro; G. Laurencin; A. Friederich; M. Razeghi R. Bisaro, G. Laurencin, A. Friederich, M. Razeghi; An accurate method to check chemical interfaces of epitaxial III‐V compounds. Appl. Phys. Lett. 1 June 1982; 40 (11): 978–980.-- June 1, 1982 We have developed a method of chemical beveling coupled with line scan Auger measurements to check abrupt interfaces of epitaxial III‐V compounds. Interface widths between 53 and 89 Å have been measured by this method for an InP/Ga0.47In0.53As/InP double heterostructure grown by low pressure metalorganic chemical vapor deposition. The ultimate width checkable by this method lies between 10 and 15 Å and is of the order of magnitude of the escape depth of the Auger electrons selected.
809.	Two‐dimensional electron gas in a In0.53Ga0.47As‐InP heterojunction grown by metalorganic chemical vapor deposition Y. Guldner; J. P. Vieren; P. Voisin; M. Voos; M. Razeghi; M. A. Poisson Y. Guldner, J. P. Vieren, P. Voisin, M. Voos, M. Razeghi, M. A. Poisson; Two‐dimensional electron gas in a In0.53Ga0.47As‐InP heterojunction grown by metalorganic chemical vapor deposition. Appl. Phys. Lett. 15 May 1982; 40 (10): 877–879.-- April 15, 1982 We report, from Shubnikov-de Haas and cyclotron resonance experiments, the first observation of a two-dimensional, high-mobility electron gas in a selectively doped 1110.53 G~l.47 As-InP heterojunction grown by metalorganic chemical vapor deposition. Several parameters of the electronic system under consideration are determined. reprint
810.	TEG IN LP-MO CVD Ga 0 4 7 ln 0 S3 As-lnP SUPERLATTICE M. RAZEGHIM. A. POISSONJ. P. LARIVAINB. de CREMOUXJ. P. DUCHEMIN ELECTRONICS LETTERs, 1982 ,Vol. 18-- April 15, 1982 We report the first successful growth of Ga o .4. 7 In 0 . J3 As-InPsuperlattice by the low-pressure metalorganic chemicalvapour deposition technique, and evidence for TEG proper-ties in these structures. reprint
811.	LOW TEMPERATURE PHOTOLUMINESCENCE AND ABSORPTION OF Ga x In 1-x As/ InP K.H. ~oetz, A.V. Solomonov , D. Bimberg , H. ~ür~ensen; M. ~azeghi+ and J. Selders* JOURNAL DE PHYSIQUE-- January 1, 1982 Optical, crystallographic and transport proptrties of nominally undoped n-type and Zn doped p-type Ga,1n1-~As (0.44 cx< 0.49) grown by LPE, VPE, and iiIOCVD are studied and related to the different growth methods. Samples grown by LPE show much larger luminescence intensities than the MOCVD and VPE samples and less structural and compositional inhomogeneities. Peaks related to free and bound excitons and to different impurities are found in the photoluminescence and absorption spectra of the undoped samples. The binding energy of the exciton is determined to 2.l'O.lmeV in agreement with hydrogenic theory. An LO phonon energy of 32~0.5meV is derived £rom LO phonon replica of the exciton line. The dependence of the energy gap at T=2K £rom the solid solution composition in the range x=44%. ..49% is determined yielding a bowing parameter of C=0.475 and a gap value of Eq=0.811eV at optimum lattice match. Data on donor-acceptor-pair transitions observed in the photoluminescence spectra are combined with secondary ion mass spectrometry data to identify for the first time different acceptors: Cr Zn, and Si. Their binding energies are 13+lmeV, 22?1meV, and 25'lmeV, respectively. C is the dominant acceptor in the MOCVD samples. but is hardly present in the LPE and VPE samples, whereas Si and Zn are unintentionally both present in LPE, VPE, and MOCVD samples. The Zn doped p-type samples showed only a broad donorZn acceptor pair transition band with a weak LO phonon replica of this band and a very weak exciton line.
812.	EPR Investigations of a Structural Phase Change in Lead Phosphate M. RAZEGHI M. RAZEGHI: EPR Investigations of a Structural Phase Change phys. stat. sol. (b) 108, 175 (1981)-- November 1, 1981 The temperature dependence of the EPR line width of the Mn2+ and Gd3+ in Pb3(PO4)2 is investigated from -270 to 500 °C. At the first-order ferroelastic transition point (180 °C), an abrupt change in the fine-structure splitting as well as in the resonance line width is observed. Various contributions to fine structure D and E parameters of Mn2+ and Gd3+ are computed, using a point-multipole model. For temperatures near to Tc the correlation time of the fluctuations is estimated to be greater than 10−9. reprint
813.	1-5 jim ROOM-TEMPERATURE PULSED OPERATION OF GalnAsP/lnP DOUBLE HETEROSTRUCTURE GROWN BY LP MOCVD Manijeh Razeghi, P. Hirtz, J.P. Larivain, R. Blondeau, B. de Crémoux, J.P. Duchemin, ELECTRONICS LETTERS, vol. 17, no.18-- September 3, 1981 The letter reports the first successful room-temperature pulsed operation of a broad-area contact laser of GaInAsP/InP double heterostructure, grown by LP MOCVD, emitting at 1.5 μm. Pulsed thresholds as low as 2.5 kA/cm2 have been obtained for 1.5 μm, for an active layer thickness of 0.48 μm. This is equal to a current density per micrometre of 5.2 kA cm−2 μm−1. InxGa1−xAsyP1−y, III, III, V, V alloys are of great interest for use in infra-red devices. They can be grown lattice matched on InP over a wide range of compositions. The resulting bandgap (1.35–0.75 eV) covers a spectral range which contains the region of lowest losses and lowest dispersion in modern optical fibres. This property makes In1−xGaxASyP1−y, very attractive as a semiconductor laser and detector material for future fibre communication systems. reprint
814.	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 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
815.	EPR investigation of Gd3+ and Eu2+ in the α- and β-phases of lead phosphate M. RAZEGHI, J. P. BUISSON, and B. HOULIE M. RAZEGHI et al.: EPR Investigation of Gd3+ and Eu2+ in Lead Phosphate phys. stat. sol. (b) 96, 283 (1979-- September 1, 1979 The X-band EPR spectra of Gd3+and Eu2+diluted in Pb3(P04)2crystals are studied. Lead phos-phate exhibits a ferroelastic phase transition a t 180 “C and the EPR spectra obtained in eachphase differ from each other. The spectra are very complex because the zero field splitting hasthe same order of magnitude as the Zeeman term. The spin Hamiltonian parameters and theenergy levels are computed. “Forbidden” or “missing” transitions and line intensities can beexplained. reprint
816.	EPR Study of Gd around the Ferroelastic Transition Point of Pb3 (PO4)2 M. RAZEGHI and B. HOULIER M. RAZEGHI et al., phys. stat. sol. (b) 89, K135 (1978) -- October 1, 1978reprint
817.	EPR STUDY OF Mn 2. AROUND THE FERROELASTIC TRANSITION POINT OF Pb3(PO4)2 M. Razeghi, B. Houlier and M. Yuste M. Razeghi et al. EPR STUDY OF Mn 2. AROUND THE FERROELASTIC TRANSITION POINT OF Pb3(PO4)2, Solid State Communications, Vol. 26, pp. 665-668. -- January 26, 1978 The spin Hamiltonian parameters of Mn 2÷ have been measured above and below the transition point (180"C) of the lead phosphate. They show that Mn 2+ substitutes a Pbl ion. Between 175 and 180vC the principal axis OX of the fine tensor is parallel to the wave vector of the soft mode which condensates at the transition point. An exaltation of the linewidth is observed. The linewidth remains constant within 50C of Te; in this temperature range, the "static regime" is achieved, and the correlation time of the fluctuations is less than 10 -s sec. reprint
818.	Neutron Activation Analysis of an Iranian Cigarette and its Smoke Z. Abedinzadeh, M. Razeghi and B. Parsa Z. Abedinzadeh, M. Razeghi and B. Parsa, Journal of Radioanalytical Chemistry, VoL 35 [1977) 373-376-- September 1, 1977 Non-destructive neutron activation analysis, employing a high-resolution Ge(Li) detector, was applied to determine the concentration of 24 trace elements in the tobacco of the Zarrin cigarette which is commercially made in Iran. These elements are: Na, K, Sc, Cr, Mn, Fe, Co, Zn, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Au, Hg and Th. The smokes from the combustion of this tobacco and of the cigarette paper were also analysed for these elements and the percentage transference values were calculated. reprint

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