The impact of extended defects on the generation and recombination lifetime in n type In_.53Ga_.47As

The relationship between the threading dislocation density (TDD), the generation (τ _g) and recombination lifetime (τ _r) in relaxed n-type In_.53Ga_.47As is investigated for a series of p+n junction diodes, containing a TDD ranging from 10⁵ to 10¹⁰ cm⁻². The TDs are generated intentionally by lattice-misfit growth on semi-insulating (SI) InP and GaAs substrates. The lifetimes have been extracted from diode current–voltage (I–V) and photoluminescence (PL) analysis showing that TDDs affect their values above a density of about 1  ×  10⁷ cm⁻² (τ _{g,E ∼ 0}) and about 1  ×  10⁸ cm⁻² (τ _r and τ _PL), which can be well-explained by the charged dislocation cylinder model. In addition, a detailed comparison between the results from deep level transient spectroscopy and from the diode characterization is performed, showing that the responsible G/R center shifts toward mid-gap in In_.53Ga_.47As and transfers from a native point defect (PD1) to a TD (E2/H1). Finally, the classical concept of generation lifetime and recombination lifetime in terms of dislocations is discussed based on the results. (paper)