EBIC INVESTIGATIONS OF EXTENDED DEFECTS IN CdTe

Abstract

The EBIC and remote contact EBIC (REBIC) techniques have been used to reveal grain boundaries and precipitates in CdTe crystals and to study their recombination contrast as a function of the electron beam parameters and temperature. The results obtained are discussed taking into account the defect charge state and the recombination properties of their environment.

Photomagnetic investigations of grain boundaries in solar silicon

“…The change in sign of the magnetic signal indicates a change in the direction of the horizontal magnetic field component sensed by the magnetometer when a grain boundary is scanned. The black-white grain boundary contrast is very similar in shape to REBIC contrasts obtained from charged defects in semiconductors [12]. In these measurements the typical black-white contrast is attributed to the different orientation of the built-in electric field on either side of a charge-separating defect.…”

“…There are several different EBIC and LBIC configurations, which commonly make use of a barrier structure (pnjunction [9] or Schottky contact [10]) in the sample. Configurations which do not incorporate a pn-or Schottky contact, but directly sense the electric field of chargeseparating defects in semiconductors, are denoted as remote contact methods (REBIC) [11,12]. Solar cells have been the subject of extensive EBIC and LBIC measurements as they inherently incorporate a pn-junction and contacts and because the investigation of excess carrier transport is of eminent importance for the understanding and optimization of photovoltaic devices.…”

Electron beam induced current and remote electron beam induced current assessment of chemical vapor deposited diamond films

“…Superimposed on it appears the EBIC signal related to charged defects that typically corresponds to dislocations, precipitates, and grain boundaries. 15,16,24 V. CONCLUSIONS EBIC measurements on diamond films reveal regions of enhanced recombination. These regions correspond mainly to ͑100͒ faces in ͑100͒ epitaxial oriented thin films.…”

Electron beam induced current and scanning tunnelling spectroscopy correlative study of and CdTe crystals

“…The bright-dark contrast of the defects shown in figure 3 is due to their built-in potential barriers, which are stable under the electron beam excitation used. The REBIC contrast decreases as the incident beam current increases, indicating a potential barrier reduction with an increase of the excitation level [20,21]. EBIC contrast is also observed in CdTe as illustrated in figure 4, which shows a twin boundary that appears as a dark line crossing from top to bottom of the micrograph.…”

“…In the REBIC image (figure 3) of the same area shown at higher magnification in figure 1(a), bright-dark stripes are related to the spatially varying surface electrostatic potential. It has previously been reported that the REBIC technique is very useful for detecting potential relief in PbTe:In(Cd) heterophase systems [19] and for revealing charged defects in CdTe and Cd x Hg 1−x Te crystals [20][21][22]. The bright-dark contrast of the defects shown in figure 3 is due to their built-in potential barriers, which are stable under the electron beam excitation used.…”