论文标题
N型硅和锗的电子顺磁共振，用于3D温度计
Electron paramagnetic resonance of n-type silicon and germanium for applications in 3D thermometry
论文作者
论文摘要
虽然存在几种2D温度测定技术，但缺乏3D温度计技术，可用于广泛的材料，并在时间，空间和温度方面提供良好的分辨率。 X射线衍射（XRD）和核磁共振（NMR）成像可以提供3D温度信息。但是，XRD通常仅限于结晶材料，而NMR在很大程度上仅限于共振线狭窄的液体。我们研究了3D温度计N型硅和锗的电子顺磁共振（EPR）。尽管在锗中，EPR线宽太宽，但硅中的EPR线宽相当窄，并且表现出强烈的温度依赖性。 N型Si中低掺杂浓度的N型SI传导电子的温度依赖性（1/T1）遵循声子扩大而导致T^3定律。对于重掺杂的Si，对于在温度计中应用良好的信号与噪声比（SNR）是可取的，预计杂质散射将降低1/T1的温度依赖性。我们的结果表明，在掺杂的N型Si中，由杂质散射引起的自旋晶格松弛并不能大大降低EPR线宽的温度依赖性。在供体浓度为7 x 10^18 /cm^3的p掺杂Si中，EPR线宽具有T^（5/2）温度依赖性；当供体浓度为7 x 10^19 /cm^3时，温度依赖性降低到T^（3/2）。虽然线宽的温度依赖性降低了较重的掺杂，但EPR线宽仍然是一个敏感的温度计。我们从N型Si的EPR线宽来定义了SNR的功绩图，并观察到增加掺杂会导致更好的SNR。使用有效的培养基理论，我们表明EPR线宽可以是一种敏感的温度计，用于在3D温度计中使用嵌入重掺杂的N型SI的微粒的系统中。
While several 2D thermometry techniques exist, there is a lack of 3D thermometry techniques that work for wide range of materials and offer good resolution in time, space and temperature. X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) imaging can provide 3D temperature information. However, XRD is typically limited to crystalline materials while NMR is largely limited to liquids where the resonance lines are narrow. We investigate electron paramagnetic resonance (EPR) of n-type silicon and germanium for 3D thermometry. While in germanium the EPR linewidths are too broad, EPR linewidths in silicon are reasonably narrow and exhibit a strong temperature dependence. The temperature dependence of the spin-lattice relaxation rate (1/T1) of conduction electrons in n-type Si for low dopant concentrations follows a T^3 law due to phonon broadening. For heavily doped Si, which is desirable for good signal to noise ratio (SNR) for application in thermometry, impurity scattering is expected to decrease the temperature dependence of 1/T1. Our results show, in heavily doped n-type Si, spin-lattice relaxation induced by impurity scattering does not drastically decrease the temperature dependence of EPR linewidths. In P-doped Si with donor concentration of 7 x 10^18 /cm^3, the EPR linewidth has a T^(5/2) temperature dependence; the temperature dependence decreases to T^(3/2) when the donor concentration is 7 x 10^19 /cm^3. While the temperature dependence of linewidth decreases for heavier doping, EPR linewidth is still a sensitive thermometer. We define a figure of merit for SNR for thermometry from EPR linewidths of n-type Si and observe that increasing the doping results in a better SNR. Using effective medium theory, we show that EPR linewidth can be a sensitive thermometer for application in 3D thermometry with systems embedding microparticles of heavily doped n-type Si.
