Electronic Structure Mapping via Correlative Scanning Photocurrent and Electron Beam Induced Current Microscopies

We demonstrate a correlative microscopy technique relating electron beam induced current (EBIC) and scanning photocurrent measurements to map out the electronic structure of active regions of semiconductor junctions and device structures, including boundary and edge effects.  Comparisons between the two microscopies provide a clearer picture of the electronic properties of samples than either individual technique allows.  Varying electron beam and laser energy in these complementary techniques enables electronic level mapping above and below the band gap as well as at various penetration depths.

Optical measurements are performed using a custom home-built confocal microscope with a 4-focus system and voice coil driven fast steering mirror to enable rapid laser scanning over a wide sample area.  This project is a result of a collaboration between Lafayette College and Ephemeron Labs; Ephemeron Labs is developing an open-source software package and scan controller to control and correlate scanning electron beam and scanning laser microscopies.