Defect Trapping in InGaAsN Measured by Deep-Level Transient Spectroscopy

Deep-level defects in p-type InGaAsN films grown by metal-organic chemical vapor deposition and molecular-beam epitaxy are investigated by deep-level transient spectroscopy (DLTS). A series of as-grown samples having varying N and In composition showed a deep hole trap with an activation energy ranging from 0.6 to 0.8 eV and an electron trap with an activation energy ranging from 0.1 to 0.4 eV.The electron trap activation energy decreased with increasing N content. Optical DLTS measurements similarly revealed the shallow electron traps, but did not show the deeper hole-trap peaks. A deep electron trap was detected when using forward bias to inject electrons during pulse filling. Together, the deep electron trap and deep hole trap may form a recombination center. This also suggeststhat generated carriers could recombine quickly, and therefore, such a recombination center may have prevented a deep-trap signal during optical DLTS.