Minority carrier lifetime and diffusion length in HgTe/CdTe superlattices by molecular beam epitaxy

Abstract
Transient minority carrier lifetime and steady state diffusion length measurements have been performed on n‐type HgTe/CdTe superlattices grown on CdZnTe(100) substrates. The n‐type (100) superlattice sample shows a lifetime of 90–100 ns at 77–160 K which then decreases with increasing temperature down to 50 ns near 300 K. p‐type HgTe/CdTe superlattices show normal behavior for temperature‐dependent lifetimes. The measured lifetime is approximately 20 ns at 77 K and increases continuously to 85 ns at 300 K. An independent measurement of minority carrier diffusion length in a p‐type HgTe/CdTe superlattice has led to an excellent agreement with a transient lifetime value of 66 ns at 200 K. The minority carrier diffusion length in a direction parallel to the interfaces indicates that the lateral transport properties are not much different from the transport properties of bulk HgCdTe.