Parameters of multilevel structure of the DX centre in GaAlAs from pressure studies of the Hall effect

Piotrzkowski, R.; Litwin‐Staszewska, E.; Lorenzini, P.; Robert, Jean-Louis

doi:10.1088/0268-1242/7/1/018

Cited by 19 publications

(5 citation statements)

References 10 publications

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“…Random potentials due to ionized impurities gave up to 40 meV Gaussian broadening in GaAs:Si. The alloy splitting of impurity states could be similar to that in AlGaAs where it was shown to exceed 100 meV [3]. This is the most probable source of broad distribution of p(E) in our In 0.5 Ga0.5P samples.…”

Section: Is Valid Under Two Assumptions: (I) That P(ε) Is Slowly Varysupporting

confidence: 64%

Electrical Properties of InGaP Doped with Si

et al. 1998

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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(ΕF). 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 p(E) in a wide energy range. We discuss the possible reasons for the observed broad distribution of p(E).PACS numbers: 72.20. Fr, 72.80.Ey, 71.55.Eq InGaP lattice matched to GaAs (i.e. with 48% of indium) is an important material for red-emitting laser diodes. For the MBE growth of n-type InGaP the Si donor is commonly used. However, there is very little data in the literature concerning the electrical properties of this material. We have studied epitaxial layers (around 1 micron thick) of InGaP:Si grown by ALMBE and MBE on semi-insulating GaAs. Hall concentration n in our samples (at T = 300 K) varied from 2 x 10 17 cm -3 up to 5 x 10 18 cm -3 . In this range we are above the Mott transition and we can neglect the effect of surface states (it is believed that InGaP has a much lower density of surface states as compared to AlGaAs). We measured n and mobility μ as functions of pressure Ρ (up to 20 kbar) and temperature T (from 20 to 300 K) using the gas cell up to 1.2 GPa and the liquid cell for higher pressures. The temperature variation of electron concentration was rather weak and similar to the literature data interpreted as due to the ionization of shallow-impurity levels [1]. However, the pressure variation of Hall concentration was substantial. This definitely eliminates the shallow-impurity interpretation. In Fig. 1 we show the n(P) dependence at 77 K for three samples. As we can see, the concentration drops for each sample. The decrease in the electron concentration (431) .

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Section: Is Valid Under Two Assumptions: (I) That P(ε) Is Slowly Varysupporting

confidence: 64%

Electrical Properties of InGaP Doped with Si

et al. 1998

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“…The first coefficient, which accounts for the Al content dependence x, equals 11 ± 1 meV/% [14], and x 0 = 22% is the percentage of aluminium at the shallow donor to deep donor transition. The temperature dependence coefficient dE d /dT is about 0.15 meV K −1 (positive Ucentre configuration) [14].…”

Section: Electron Transfer Studymentioning

confidence: 99%

Charge transfer and electron mobility in GaAlAs/GaAs modulation-doped heterostructures: the role of interface states

Sibari

Raymond

Kubisa

1996

Semicond. Sci. Technol.

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We develop a theoretical model of charge equilibrium in modulation-doped GaAlAs/GaAs heterojunctions in which the presence of donor-like interface states is considered. Assuming that the electrons occupy the first and second electronic subbands we calculate the charge transfer in the heterojunction as a function of the temperature, taking into account the metastable character of the Si donors in the GaAlAs-doped layer. We show that interface states, the density of which depends on the growth process and on the sample quality, play an important role in the temperature dependence of the charge equilibrium and allow us to explain the variation of the density of the 2D electrons with the temperature. On this basis we investigate in detail the scattering mechanisms, in order to account for the mobility limitation in the low-temperature range (T < 10 K). In this case too the role of interface states is found to be crucial. All the calculations are performed within the generalized variational subband wavefunction model.

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“…The most probable source of broad distribution of rE in our InGaP samples seems to be the alloy splitting of impurity states. In AlGaAs it was shown to exceed 100 meV [7].…”

Section: Results For Ingap : Simentioning

confidence: 99%