Correlation of electrical properties and defect states of InxGa1-xAs (x=0.53-0.93) based p-i-n photodetectors

Abstract

InxGa1-xAs (x = 0.53-0.93) based PIN photodiodes (PDs) were fabricated using a metal-organic chemical vapor deposition system. Current density vs. voltage (J-V) measurements showed that as the In content increased from 0.53 to 0.88, the reverse current density at -0.5 V decreased from 9.60 x 10- 2 to 0.56 x 10- 2 mA center dot cm- 2, while the ideality factor increased from 1.51 to 2.12, indicating enhanced trap-assisted recombination. Temperature dependent J-V analysis revealed that the Ea,c values for In0.83Ga0.17As and In0.88Ga0.12As were close to half of the bandgap energy, indicating that Shockley-Read-Hall recombination is the dominant mechanism. From deep level transient spectroscopy, H1 and E2 defects appeared at higher In content, with the H1 defect density increasing from 1.68 x 1013 to 3.60 x 1013 cm- 3. This increased in H1 defect density led to a significant decrease in detectivity from 1.30 x 1010 to 5.55 x 109 cm center dot Hz1/2/W.