Abstract

We report near-field optical-beam-induced- current (NOBIC) measurements on semiconductor-quantum-well (QW) structures. A subwavelength fiber tip is coupled with a tunable laser source and is scanned over a sample surface. The induced photocurrent reveals the compositional profile of quantum structures. Semiconductor QW structures were designed and were fabricated by molecular-beam epitaxy (MBE) to study the wavelength dependence and resolution capability of NOBIC. We demonstrate that the resolution of the probe depends strongly on the excitation wavelength because of the variation of the optical penetration depth.

© 1995 Optical Society of America