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1

Universal Behaviour of Magnetoconductance due to Weak Localization in Two-Dimensional Systems - Example of GaInAs Quantum Wells

100%

Zduniak A., Dyakonov M. I., Litwin-Staszewska E., Knap W.

Acta Physica Polonica A

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1995

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vol. 88

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issue 5

1053-1057

EN

Weak localization corrections to conductivity of a two-dimensional electron gas are studied by measurements of the magnetic field dependence of the conductivity in GalnAs quantum wells. We observe that, when presented as a function of the normalized magnetic field (x = B/B_{tr}, where B is the magnetic field, B_{tr} = ħ/4eτD, D is the diffusion constant and τ is momentum relaxation time), different samples show very similar high field behaviour. A theoretical description is developed that allows one to describe in a consistent way high and low field behaviour. The theory predicts universal (B^{-1/2}) behaviour of the conductivity correction for all 2D systems in the high field limit (r > 1). Low field behaviour depends strongly on spin and phase relaxation mechanisms. Comparison of the theory with experiment confirms the universal behaviour in the high field limit and allows one to estimate the spin and phase relaxation times for different GaInAs quantum wells.

2

Electrical Properties of InGaP Doped with Si

100%

Litwin-Staszewska E., Trzeciakowski W., Piotrzkowski R., Gonzalez L.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

431-435

EN

We measured Hall concentration n in InGaP:Si epitaxial layers grown by MBE as a function of pressure P up to 2 GPa and of temperature T from 77 to 300 K. We interpreted our results in terms of the broad distribution of impurity states resonant with the conduction band. From the low-temperature n(P) dependence we can directly obtain the total density of impurity states around the Fermi level ρ(E_{F}). The Fermi level can be shifted with respect to impurity states by applying pressure and by using samples with different n. In this way we obtain ρ(E) in a wide energy range. We discuss the possible reasons for the observed broad distribution of ρ(E).

3

Lattice Constant of Doped Semiconductor

88%

Leszczyński M., Litwin-Staszewska E., Suski T., Bąk-Misiuk J., Domagała J.

Acta Physica Polonica A

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1995

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vol. 88

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issue 5

837-840

EN

The paper shows an influence of doping on lattice constant of a semiconductor. Three effects are discussed: (i) "size" effect caused by a different ionic radii of dopant and host atoms, (ii) lattice expansion by free electrons proportionally to the deformation potential of the conduction-band minimum occupied by this charge, (iii) different thermal expansion of the undoped and doped samples. The experiments have been performed by using the high resolution X-ray diffraction at 77-770 K on AlGaAs:Te and GaAs:Si.

4

Near IR Refractive Index for GaInN Heavily Doped with Silicon

76%

Cywiński G., Kudrawiec R., Rzodkiewicz W., Kryśko M., Litwin-Staszewska E., Misiewicz J., Skierbiszewski C.

Acta Physica Polonica A

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2009

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vol. 116

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issue 5

936-938

EN

The authors report on growth and results of infrared measurements of GaInN heavily doped with silicon. The lattice matched to GaN epitaxial layer of Ga_{0.998}In_{0.002}N:Si has been grown in plasma assisted molecular beam epitaxy in the metal rich conditions. The room temperature Hall concentration and mobility of electrons are 2× 10^{20} cm^{-3} and 67 cm^{2}/(Vs), respectively. The refractive index has been determined by variable angle spectroscopic ellipsometry. The refractive index exhibited a significant reduction of its value (from 2.25 to 2 at 1.55 μm) at near IR range where are the main interests of potential applications for nitride based intersubband devices. Reported here values of refractive indices at 1.55 and 1.3 μm are appropriate for fabrication of cladding layers with the required contrast to GaN for intersubband devices. The observed drop of refractive index is attributed to the carrier-induced plasma edge effect, which has been directly observed in reflectance spectrum.

5

Spatial Correlations of Donor Charges in MBE CdTe

64%

Suski T., Wiśniewski P., Litwin-Staszewska E., Wasik D., Przybytek J., Baj M., Karczewski G., Wojtowicz T., Zakrzewski A., Kossut J.

Acta Physica Polonica A

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1995

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vol. 88

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issue 5

929-932

EN

We present experimental evidence that at high pressures indium donors in CdTe localize electrons in spatially correlated manner. We have studied Hall mobility, μ_{H}, as a function of electron concentration, n_{H}, at T=77 K. Changes of n_{H} have been achieved by two methods. High pressure freeze-out of electrons onto localized states of In-donors leads to the mobility enhancement with respect to the situation when n_{H} has been modified by means of a subsequent annealing of the sample. As a result, depending on the degree of spatial correlations in the impurity charges arrangement, different values of μ_{H} correspond to the same value of n_{H}. The variation of mobility with electron concentration suggests that the localized state of In-donor represents likely negatively charged DX state.

6

Weak Antilocalization in Quantum Wells

64%

Knap W., Skierbiszewski C., Litwin-Staszewska E., Kobbi F., Zduniak A., Robert J., Pikus G., Iordanskii S., Mosser V., Zekentes K.

Acta Physica Polonica A

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1995

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vol. 87

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issue 2

427-432

EN

Spin relaxation in degenerated two-dimensional (2D) electron gas is studied by measurements of the magnetic field dependence of the weak antilocalization corrections to the conductivity in GaInAs quantum wells. Consistent quantitative (up to order of magnitude) description of weak antilocalization data on GaAs like heterojunctions and quantum wells was obtained. Our results show that spin precession around the effective magnetic field direction as described by the Dyakonov-Perel model is the main spin relaxation mechanism in degenerated 2D electron gas in semiconductors with no inversion symmetry.

7

III-V Semiconducting Nitrides Energy Gap under Pressure

64%

Perlin P., Gorczyca I., Teisseyre H., Suski T., Litwin-Staszewska E., Porowski S., Grzegory I., Christensen N.

Acta Physica Polonica A

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1992

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vol. 82

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issue 4

674-676

EN

In this paper we present overview of our recent experimental and theoretical results concerning electronic band structure of III-V nitrides under pressure. It is shown here that the pressure coefficients of the direct gap for studied nitrides are surprisingly small. To describe tendency in changes of the gap with pressure we use a simple empirical relation.

8

Two-Electron DX State in CdTe:In

64%

Skierbiszewski C., Wiśniewski P., Litwin-Staszewska E., Suski T., Wilamowski Z., Zakrzewski A., Karczewski G., Jantsch W.

Acta Physica Polonica A

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1996

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vol. 90

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issue 5

927-930

EN

In this paper we investigate electron emission/capture from/to the DX state of indium in CdTe by means of high pressure freeze-out cycle and steady-state photo-conductivity experiments. The results indicate that the DX state is occupied by two electrons. A comparison with deep level transient spectroscopy data shows that two-electron emission occurs at low temperatures, while one-electron emission takes place at high temperatures.

9

High Resistivity GaN Single Crystalline Substrates

52%

Porowski S., Boćkowski M., Łucznik B., Grzegory I., Wróblewski M., Teisseyre H., Leszczyński M., Litwin-Staszewska E., Suski T., Trautman P., Pakuła K., Baranowski J.

Acta Physica Polonica A

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1997

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vol. 92

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issue 5

958-962

EN

High resistivity 10^{4}-10^{6} Ω cm (300 K) GaN single crystals were obtained by solution growth under high N_{2} pressure from melted Ga with 0.1-0.5at.% of Mg. Properties of these crystals are compared with properties of conductive crystals grown by a similar method from pure Ga melt. In particular, it is shown that Mg-doped GaN crystals have better structural quality in terms of FWHM of X-ray rocking curve and low angle boundaries. Temperature dependence of electrical resistivity suggests hopping mechanism of conductivity. It is also shown that strain free GaN homoepitaxial layers can be grown on the Mg-doped GaN substrates.

10

High Temperature Stability of Electrical and Optical Properties of Bulk GaN:Mg Grown by HNPS Method in Different Crystallographic Directions

52%

Sadovyi B., Amilusik M., Staszczak G., Bockowski M., Grzegory I., Porowski S., Konczewicz L., Tsybulskyi V., Panasyuk M., Rudyk V., Karbovnyk I., Kapustianyk V., Litwin-Staszewska E., Piotrzkowski R.

Acta Physica Polonica A

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2016

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vol. 129

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issue 1a

A-126-A-128

EN

Single crystals of Mg-doped GaN grown by high nitrogen pressure solution method in different crystallographic directions ([0001], [101̅1], and [101̅1̅]) were investigated in order to determine thermal stability of their electrical and optical properties. Obtained dependences of resistivity, the Hall coefficient and energy shift of Mg-related photoluminescence peak on annealing temperature allow to suggest that incorporation of Mg in GaN is significantly influenced by the direction of the crystallization front.

11

Polarity Related Problems in Growth of GaN Homoepitaxial Layers

52%

Leszczyński M., Prystawko P., Śliwinski A., Suski T., Litwin-Staszewska E., Porowski S., Paszkiewicz R., Tłaczała M., Beaumont B., Gibart P., Barski A., Langer R., Knap W., Frayssinet E.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

427-430

EN

Homoepitaxial layers of GaN were grown by metalorganic chemical vapour deposition on single crystals obtained by high-pressure, high-temperature technology. For each metalorganic chemical vapour deposition run, four samples were placed, (00.1) and (00.1̲) faces of the Mg-doped insulating and undoped highly-conductive substrates. The layers were examined using X-ray diffraction, photoluminescence and far-infrared reflectivity. It was found that the (00.1̲) easier incorporates donors resulting in higher free-electron concentrations in the layers grown on these sides of the crystals, both, undoped and Mg-doped.

12

Blue Laser on High N_2 Pressure-Grown Bulk GaN

40%

Grzegory I., Boćkowski M., Krukowski S., Łucznik B., Wróblewski M., Weyher J., Leszczyński M., Prystawko P., Czernecki R., Lehnert J., Nowak G., Perlin P., Teisseyre H., Purgał W., Krupczyński W., Suski T., Dmowski L., Litwin-Staszewska E., Skierbiszewski C., Łepkowski S., Porowski S.

Acta Physica Polonica A

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2001

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vol. 100

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issue Supplement

229-232

EN

In this note we report briefly on the details of pulsed-current operated "blue" laser diode, constructed in our laboratories, which utilizes bulk GaN substrate. As described in Ref. [1] the substrate GaN crystal was grown by HNPSG method, and the laser structure was deposited on the conducting substrate by MOCVD techniques (for the details see Sec. 2 and Sec. 4 of Ref.~[1], respectively).

Refine search results

Universal Behaviour of Magnetoconductance due to Weak Localization in Two-Dimensional Systems - Example of GaInAs Quantum Wells

Electrical Properties of InGaP Doped with Si

Lattice Constant of Doped Semiconductor

Near IR Refractive Index for GaInN Heavily Doped with Silicon

Spatial Correlations of Donor Charges in MBE CdTe

Weak Antilocalization in Quantum Wells

III-V Semiconducting Nitrides Energy Gap under Pressure

Two-Electron DX State in CdTe:In

High Resistivity GaN Single Crystalline Substrates

High Temperature Stability of Electrical and Optical Properties of Bulk GaN:Mg Grown by HNPS Method in Different Crystallographic Directions

Polarity Related Problems in Growth of GaN Homoepitaxial Layers

Blue Laser on High N_2 Pressure-Grown Bulk GaN