Strain relaxation of CdTe films growing on lattice-mismatched substrates

Zhixun Ma, Kin Man Yu, Wladek Walukiewicz, Peter Y. Yu, Samuel S. Mao

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We have deposited CdTe films by laser-assisted epitaxy approach and investigated the influence of substrate and film thickness on the film properties. Grown on Si(001), GaAs(001), and quartz substrates; the CdTe films exhibit preferential orientation along the cubic CdTe(111) direction. When the films are thin (<500 nm), a blueshift of the band gap and splitting of valence bands were observed. These results are attributed to the existence of residual strains induced by mismatch of the film lattice constant with that of the substrate, and by their difference in thermal expansion coefficients. The bulk band-gap energy of 1.5 eV was achieved on the surface of thick CdTe films grown on Si(001) substrate, indicating that strain was almost completely relaxed in this case. Our results demonstrate that by a proper selection of substrate and film thickness it is possible to grow film semiconductors with band gap approaching those of bulk crystals.

Original languageBritish English
Pages (from-to)379-384
Number of pages6
JournalApplied Physics A: Materials Science and Processing
Volume96
Issue number2
DOIs
StatePublished - Aug 2009

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