We report specific heat and thermal conductivity of gadolinium- andyttrium-doped amorphous silicon thin films measured using silicon-nitridemembrane-based microcalorimeters. Addition of gadolinium or yttrium to theamorphous silicon network reduces the thermal conductivity over a widetemperature range while significantly increasing the specific heat. This resultindicates that a large number of non-propagating states are added to thevibrational spectrum that are most likely caused either by localized vibrationof the dopant atom in a Si cage, or softening of the material forming the cagestructures. High-resolution cross-sectional electron micrographs revealcolumnar features in Gd-doped material which do not appear in pure amorphoussilicon. Scattering from both the nanoscaled columns and the filled-cagestructures play a role in the reduced thermal conductivity in the rare-earthdoped amorphous semiconductor. The overall result is an amorphous solid with alarge bump in $C/T^{3}$ and no plateau in thermal conductivity.
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机译：我们报告了使用基于氮化硅膜的量热仪测量的do和钇掺杂的非晶硅薄膜的比热和热导率。在非晶硅网络中添加g或钇会在较宽的温度范围内降低热导率，同时会显着提高比热。这表明大量的非传播态被添加到振动光谱中，这很可能是由于Si笼中掺杂原子的局部振动或形成笼结构的材料的软化所致。高分辨率的横截面电子显微照片揭示了掺G的材料中的柱状特征，而纯非晶硅中则没有。来自纳米级柱和填充笼结构的散射在稀土掺杂非晶半导体的热导率降低中起作用。总体结果是非晶固体，具有$ C / T ^ {3} $的大凸点且导热率没有平台。
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