High-resolution electron energy-loss spectroscopy at epitaxially grown GaAs(100)

Electron‐phonon‐plasmon interaction in MBE‐grown indium nitride – A high resolution electron energy loss spectroscopy (HREELS) study

“…The latter result from the coupling between phonon and plasmon excitations [7][8][9]. In the simulation we use a model, which has been successfully applied to in-situ HREELS data for homogeneously and δ-doped GaAs(001) films grown by MBE [2,3,10]. To simulate the measured HREELS-spectra, knowledge of the electron density distribution versus depth beneath the surface is required.…”

“…However, if the carrier concentration is sufficiently high, a well separated and defined loss peak can be detected, as shown for example for MBE-grown GaAs(001) [2]. In case of a surface plasmon energy very close to that of the surface optical phonon, the two excitations are not independent anymore, they couple to form two new modes, each of which may be regarded as an admixture of the surface optical phonon and the surface plasmon.…”

“…In conjunction with theoretical calculations this technique has been proven to provide relevant information about semiconductors and their surfaces, e.g. free-carrier concentrations in the bulk and in the subsurface regime, band bending, electron mobility and plasmaron damping for homogeneously δ-doped materials [2,3]. In order to calculate energy-loss spectra, knowledge of the free-electron density profile is required.…”

“…These coupled modes were first observed by Matz and Lüth [4] for n-type GaAs(110). In order to illustrate the influence of the doping level Si was used as a dopant during MBE growth of GaAs(001) in different depths and different ways (δ-doping, homogeneous bulk doping) [2,3]. In this contribution InN(0001) was grown on GaN without intentional doping.…”

Atomic hydrogen cleaning of GaSb(001) surfaces

“…In particular, the active donor concentration is not reduced due to the indiffusion of atomic hydrogen, which has previously been observed to reduce the subsurface carrier concentration in heavily doped GaAs after room temperature exposure. 23 In conclusion, we have demonstrated that GaSb͑001͒ surfaces may be efficiently cleaned by exposure to atomic hydrogen at 400-470°C with molecular hydrogen doses of 100-150 kL. After 100 kL at 400°C the surfaces are free of contamination, as determined by AES.…”