2015/06/13 by Daniel Queen, D. R. Queen, X. Liu +7 · 1 citation
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Amorphous silicon #Amorphous solid #Chemical physics #Chemistry #Condensed matter physics #Crystalline silicon #Crystallography #Materials science #Molecular physics #Optoelectronics #Phase-change materials and chalcogenides #Physics #Silicon #Silicon Nanostructures and Photoluminescence #Thin-Film Transistor Technologies #cond-mat.dis-nn #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.jnoncrysol.2015.06.020
arxiv created 2015/06/13 · openalex publication_date 2015/06/24 · arxiv updated 2020/11/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In e-beam evaporated amorphous silicon (a-Si), the densities of two-level systems (TLS), n0 and P, determined from specific heat C and internal friction Q-1 measurements, respectively, have been shown to vary by over three orders of magnitude. Here we show that n0 and P are proportional to each other with a constant of proportionality that is consistent with the measurement time dependence proposed by Black and Halperin and does not require the introduction of additional anomalous TLS. However, n0 and P depend strongly on the atomic density of the film (n\rm Si) which depends on both film thickness and growth temperature suggesting that the a-Si structure is heterogeneous with nanovoids or other lower density regions forming in a dense amorphous network. A review of literature data shows that this atomic density dependence is not unique to a-Si. These findings suggest that TLS are not intrinsic to an amorphous network but require a heterogeneous structure to form.