Deep Levels in p-Type InGaAsN Lattice Matched to GaAs;Applied Physics Letters

摘要

Deep level transient spectroscopy (DLTS) measurements were utilized to investigate deep level defects in metal-organic chemical deposition (MOCVD)-grown unintentionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the band gap, with a dominant hole trap at E(v)+0.10 eV. Post-growth annealing simplified the deep level spectra, enabling the identification of three distinct hole traps at 0.10 eV, 0.23 eV, and 0.48 eV above the valence band edge, with concentrations of 3.5x10 to the 14th power cm(-3), 3.8x10 to the 14th power cm(-3), and 8.2x10 to the 14th power cm(-3), respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4x10 to the 14th power cm(-3) in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority carrier properties after annealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level may be important for processed InGaAsN devices in the future.