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Molecular Beam Epitaxy Approach To The Graphitization Of Gaas(100) Surfaces, Paul J. Simmonds, John Simon, Jerry M. Woodall, Minjoo Larry Lee
Molecular Beam Epitaxy Approach To The Graphitization Of Gaas(100) Surfaces, Paul J. Simmonds, John Simon, Jerry M. Woodall, Minjoo Larry Lee
Paul J. Simmonds
The authors present a method for obtaining graphitized carbon on GaAs(100) surfaces. Carbon-doped GaAs is grown by molecular beam epitaxy before controlled thermal etching within the growth chamber. An AlAs layer beneath the carbon-doped GaAs acts as a thermal etch stop. As the GaAs is etched away, the carbondopant atoms remain on the surface due to their low vapor pressure. The total number of carbon atoms available is precisely controllable by the doping density and thickness of the carbon-doped GaAs layer. Characteristic phonon modes in Raman spectra from the thermally etchedsurfaces show that the residual surfacecarbon atoms form sp2 …
Graphitized Carbon On Gaas(100) Substrates, J. Simon, P. J. Simmonds, J. M. Woodall, M. L. Lee
Graphitized Carbon On Gaas(100) Substrates, J. Simon, P. J. Simmonds, J. M. Woodall, M. L. Lee
Paul J. Simmonds
We report on the formation of graphitized carbon on GaAs(100) surfaces by molecular beam epitaxy. We grew highly carbon-doped GaAs on AlAs, which was then thermally etched in situ leaving behind carbon atoms on the surface. After thermal etching, Raman spectra revealed characteristic phonon modes for sp2-bonded carbon, consistent with the formation of graphitic crystallites. We estimate that the graphitic crystallites are 1.5–3 nm in size and demonstrate that crystallite domain size can be increased through the use of higher etch temperatures.
Quantum Dot Resonant Tunneling Diode For Telecommunication Wavelength Single Photon Detection, H. W. Li, B. E. Kardynał, P. See, A. J. Shields, P. Simmonds, H. E. Beere, D. A. Ritchie
Quantum Dot Resonant Tunneling Diode For Telecommunication Wavelength Single Photon Detection, H. W. Li, B. E. Kardynał, P. See, A. J. Shields, P. Simmonds, H. E. Beere, D. A. Ritchie
Paul J. Simmonds
The authors present a quantum dot (QD) based single photon detector operating at a fiber optic telecommunication wavelength. The detector is based on an AlAs/In0.53Ga0.47As/AlAs double-barrier resonant tunneling diode containing a layer of self-assembled InAs QDs grown on an InP substrate. The device shows an internal efficiency of about 6.3% with a dark count rate of 1.58 × 10−6 ns−1 for 1310 nm photons.