Full text loading...
Luminescence spectrum recorded at a sample voltage and tunneling current over an exposure time of 1 s. The spectrum is corrected for detector response.
Schematic energy diagram of the tunneling junction with negative bias applied to the -type GaAs sample. Most of the tunneling current is due to tunneling from the CB minimum , which determines the topographic image. A small current component (1) originates from states near the VB maximum and (2) generates holes at the VB maximum which (3) recombine with conduction band electrons.
(a) STM topograph ( ; ; and ) of a terrace of GaAs(110) and (b) map of the photon intensity with wavelengths acquired simultaneously. (c) Superposition of maxima in topographic (dark gray) and intensity (light gray) maps. A unit cell at identical lattice positions is indicated in each image.
Calculated energies of CB minimum and VB maximum along with Fermi energy of the tip vs sample voltage. Energies are measured with respect to the Fermi energy of the sample. Dotted, dotted-dashed, and solid lines correspond to doping levels , , and , respectively. Further parameters: tip work function 4.5 eV, tip-sample distance 0.9 nm, and donor level 5.8 meV.
Article metrics loading...