Lifetime Assessment of In x Ga 1− x As n‐Type Hetero‐Epitaxial Layers

Herein, the carrier lifetime in approximately 5x10^16 cm^(-3) n-doped In(x)Ga(1-x)As layers is studied by diode current–voltage analysis and by time-resolved photoluminescence. Two sets of hetero-epitaxial layers are grown on semi-insulating InP or GaAs substrates. The first set corresponds with a constant In content p + n stack, while the second set has a fixed x = 0.53 for the n-layer, while containing various extended defect densities by using a strain relaxed buffer with different x. This results in threading dislocation densities (TDDs) between approximately 10^5 cm^(-2) and a few 10^9 cm^(-2). It is shown that the overall trend of the recombination lifetime versus TDD can be described by a first-order model considering a finite recombination lifetime value inside a dislocation core of 1 nm. For the generation lifetime, a strong electric-field enhancement factor is found. Also, the residual strain in the n-layer has an impact. Overall, the safe limit for TDD depends on the type of application and on the operation conditions (reverse diode bias).