Investigation of Nanoscale Electronic Properties of Undoped InAs/GaSb Superlattice by Spreading Resistance Microscopy

Using spreading resistance microscopy (SRM) under atmospheric conditions, we demonstrate a stable contrast of the electrical properties on the cleaved cross-section of an undoped InAs/GaSb type-II superlattice with a period of 7.5 nm. It is shown that this contrast is a consequence of the difference in the conductivity of the InAs and GaSb layers of the superlattice. A simple and effective method is proposed for monitoring the structure and electron‒hole subsystem of InAs/GaSb superlattices used in modern IR photodetectors.