Electron mobility in Si δ-doped GaAs with spatial correlationsin the distribution of charged impurities

Shi, J.M.; Koenraad, PM Paul; Stadt, van de Afw; Peeters, F. M.; Farias, G. A.; Devreese, JT Jozef; Wilamowski, Ż.

doi:10.1103/physrevb.55.13093

Cited by 16 publications

(12 citation statements)

References 17 publications

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“…They can serve as a source of free carriers in modulation-doped field effect transistors 1,2 or power devices, 3 allow one to produce low-resistivity ohmic contacts 4,5 or to obtain high-field regions for studying and applying electro-optical effects, 6,7 for example. Moreover, because the ␦ doping produces a self-consistent potential well confining a two-dimensional ͑2D͒ electron system with a high degree of disorder, basic physical properties of the two-dimensional electron gas have been studied in ␦ layers mainly by magnetotransport and optical methods [8][9][10] with a special emphasis put on a detailed analysis of the influence of disorder on the transport and the localization in twodimensional systems. [11][12][13][14] An elementary characterization of the ␦ layers is often performed by a capacitance-voltage (C -V) measurement in structures where the ␦ layer is involved in a space charge region ͑SCR͒ of the Schottky barrier.…”

Section: Introductionmentioning

confidence: 99%

Deep levels in GaAs due to Si δ doping

Hubı́k

Krištofik

Mareš

et al. 2000

Journal of Applied Physics

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␦͑Si͒-doped GaAs samples grown by metalorganic vapor phase epitaxy are studied by capacitancevoltage and deep level transient spectroscopy ͑DLTS͒ techniques. A detailed analysis of the DLTS signal ͑including spatial profiles͒ is performed. DLTS spectra exhibit a clear development depending on the sheet dopant concentration ranging from 5ϫ10 14 to 2ϫ10 16 m Ϫ2 . Two observed peaks do not change its activation energy with the doping level while their amplitude increases rapidly when the doping rises. We assign them to defects generated by high silicon concentration, probably related to gallium vacancy. Another peak in the most densely doped sample seems to correspond to the DX level which is occupied near the ␦ layer. Peculiar features of the EL2 level are observed in ␦-doped GaAs and explained by the band bending due to the dopant sheet. No indication of the emission from the quantum confinement states is found in DLTS spectra taken at temperatures 80-400 K.

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Section: Introductionmentioning

confidence: 99%

Deep levels in GaAs due to Si δ doping

Hubı́k

Krištofik

Mareš

et al. 2000

Journal of Applied Physics

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“…This is not a direct prove of ordering of the scatters, because at ambient pressure the quantum mobilities also increase with decreasing electron density. A recent study of us [40] demonstrates that the self-compensation, which occurs in the samples of Skuras et al [14] makes the interpretation of their measurements very difficult. In order to demonstrate correlation effects in δ-layers it is thus necessary to avoid any self-compensation.…”

Section: The Dx-center Most Donors In Gaas Likementioning

confidence: 97%

Spatial correlation effects in the charged impurity distribution on the electronic properties of δ‐doped structures

Stadt

Koenraad²,

Shi

et al. 2003

Physica Status Solidi (b)

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Dedicated by the coauthors to Professor Jozef T. Devreese on the occasion of his 65th birthday PACS 71.55. Eq, 73.50.Dn, 73.63.Hs In this paper we will show that the δ-doped GaAs/AlGaAs/GaAs quantum barrier is an ideal system to study deep centers in narrow doping layers with high doping density. By varying the Al content in the barrier, the distance between the Fermi-level and the deep level can be tuned and therefore the number of populated states. By applying hydrostatic pressure this number can be further increased. Our measurements show that in these δ-doped barrier structures electrons are trapped under hydrostatic pressure and that the quantum mobility is enhanced. This mobility enhancement can be explained by MC calculations which include the effect of the spatial correlation of the charge distribution when the deep state is the DX center and has a negative charge state. The fact that we do not observe a PPC effect or a significant change in the mobility after illumination at high pressure suggest that the Fermi-level is pinned by a non-metastable deep state like the A 1 state or that the DX center is modified.1 Introduction The idea of positioning individual atoms on a surface is very appealing and has many futuristic applications other than a 5-atom font size [1]. Using STM atoms can be moved around and placed on the surface in any configuration. Thus we can in principle create an artificial lattice. Especially in the semiconductor field this is an attractive concept because ordering of the doping atoms is expected to increase the electrical activity [2], reduce dopant fluctuations [3] and increase the carrier mobility [4]. However for practical applications too many atoms are involved thus the ordering of impurity atoms should be self-assembling. This can be accomplished by using a modified substrate surface, which has sites to which doping atoms preferentially go. At high enough growth temperatures the impurity atoms are allowed to diffuse to these sites. This technique has been applied to reconstructed surfaces [2,5] and misaligned substrates [6]. Most of these studies were concerned with structural properties and some with the consequences of such ordering on the electronic properties [7]. These growth studies are however difficult and require a lot of samples. There is fortunately a different approach to study spatial correlation effects by obtaining ordering in the charge distribution of randomly ordered impurity atoms. This ordering cannot be as large as a full spatial ordering introduced during growth, but the degree of ordering can be changed within one structure. Such ordering in the charge distribution can be obtained using the DX state associated with the Si donor in GaAs. By applying hydrostatic pressure electrons are trapped in these states. In current models this donor state is either neutral [8] or negatively [9] charged. Thus when DX centers are populated we have a so-called multi-valence system with either positively charged and

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“…In GaAs with d layer, the electrons form a two-dimensional (2D) electron gas in the plane of the d layer. Some researchers has been undertaken to understand the electrical transport mechanisms in Si d-doped GaAs [3][4][5]. Since the lattice constant of Si (5.43Å) is smaller than the lattice constant of GaAs (5.65Å), the Si d layers have tensile strain about 4%.…”

Section: Introductionmentioning

confidence: 99%

Electrical conduction properties of Si δ-doped GaAs grown by MBE

Yıldız¹,

Li̇şesi̇vdi̇n²,

Altuntaş³

et al. 2009

Physica B: Condensed Matter

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The temperature dependent Hall effect and resistivity measurements of Si d-doped GaAs are performed in a temperature range of 25-300 K. The temperature dependence of carrier concentration shows a characteristic minimum at about 200 K, which indicates a transition from the conduction band conduction to the impurity band conduction. The temperature dependence of the conductivity results are in agreement with terms due to conduction band conduction and localized state hopping conduction in the impurity band. It is found that the transport properties of Si d-doped GaAs are mainly governed by the dislocation scattering mechanism at high temperatures. On the other hand, the conductivity follows the Mott variable range hopping conduction (VRH) at low temperatures in the studied structures.

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Electron mobility in Si δ-doped GaAs with spatial correlationsin the distribution of charged impurities

Cited by 16 publications

References 17 publications

Deep levels in GaAs due to Si δ doping

Deep levels in GaAs due to Si δ doping

Spatial correlation effects in the charged impurity distribution on the electronic properties of δ‐doped structures

Electrical conduction properties of Si δ-doped GaAs grown by MBE

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