SCANNING TUNNELING OPTICAL SPECTROSCOPY OF SEMICONDUCTOR QUANTUM-WELL STRUCTURES

Scanning tunneling optical spectroscopy has been used to determine the optical properties of semiconductor quantum wells. With this technique, photoenhanced tunneling currents are measured with a scanning tunneling microscope on heterostructures illuminated with monochromatic light. For the InAs(x)P1-x/InP strained single quantum well structures, the 295 K spectra exhibit well-resolved transitions attributable to interband transitions involving the heavy-hole valence band and the n = 1 conduction subband. The observed transition energies are in good agreement with values measured using photoconductivity and photoluminescence spectroscopy on the same samples.