Highly strained Ge1-xSnx alloy films with high Sn compositions grown by MBE

We have grown a series of Ge1-xSnx films with high Sn compositions up to 16.6% directly on Ge (100) substrates using molecular beam epitaxy (MBE). Reciprocal space mapping (RSM) study shows that all the Ge1-xSnx alloy films are highly strained even after Sn segregation has occurred. Ellipsometry measurements confirm that increasing the Sn composition shrinks the bandgap of Ge1-xSnx. We have found that low growth temperatures and high growth rates are beneficial to achieve higher Sn compositions, and strain is an important role in limiting the Sn incorporation.

Automated summary

The study found that Ge1-xSnx alloy films are highly strained even after Sn segregation, and increasing the Sn composition shrinks the bandgap of Ge1-xSnx. Low growth temperatures and high growth rates are beneficial for achieving higher Sn compositions, while strain plays an important role in limiting Sn incorporation.