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arXiv 2012.07550cond-mat.mtrl-scinucl-ex
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硅、硼掺杂对N型GaAs低温闪烁性能的影响

How Silicon and Boron Dopants Govern the Cryogenic Scintillation Properties of N-type GaAs

Stephen Derenzo, Edith Bourret, Christiane Frank-Rotsch, Stephen Hanrahan, Maurice Garcia-Sciveresa

摘要:

本文首次报道了硅和硼的浓度对n型GaAs低温闪烁特性的影响。结果表明,价带空穴被迅速捕获在辐射中心,然后以随自由载流子密度增加的速率与硅施主带电子辐射结合。它还提出了在X射线激发下有效发光所需的硅和硼浓度范围,以及其低带隙和明显没有余辉,使掺杂GaAs适合于检测来自相互作用的暗物质粒子的稀有低能电子激发。共研究了来自四个不同供应商的29个样品。测量了中心在860、930、1070和1335 nm的四个主要发射带以及总发射的亮度和定时响应。由超快激光驱动的光激发X射线管提供40 kVp X射线的激发脉冲。使用InGaAs光电倍增管测量800至1350 nm的闪烁发射。在自由载流子浓度为2 x 10^16/cm 3至6 x 10^17/cm 3,硼浓度为1.5 x 10^18/cm 3至6 x 10^18/cm 3的范围内,9个样品的亮度> 70光子/keV,2个样品的亮度> 110光子/keV。在这个范围内的其他样品由于非辐射中心的浓度较高而具有较低的光度。随着自由载流子浓度从10^17/cm 3增加到2 x 10^18/cm 3,衰减时间通常会减少10倍。

英文摘要:

This paper is the first report describing how the concentrations of silicon and boron govern the cryogenic scintillation properties of n-type GaAs. It shows that valence band holes are promptly trapped on radiative centers and then combine radiatively with silicon donor band electrons at rates that increase with the density of free carriers. It also presents the range of silicon and boron concentrations needed for efficient light emission under X-ray excitation, which along with its low band gap and apparent absence of afterglow, make scintillating GaAs suitable for the detection of rare, low-energy electronic excitations from interacting dark matter particles. A total of 29 samples from four different suppliers were studied. Luminosities and timing responses were measured for the four principal emission bands centered at 860, 930, 1070, and 1335 nm, and for the total emissions. Excitation pulses of 40 kVp X-rays were provided by a light-excited X-ray tube driven by an ultra-fast laser. Scintillation emissions from 800 to 1350 nm were measured using an InGaAs photomultiplier. Within the concentration ranges of free carriers from 2 x 10^16/cm3 to 6 x 10^17/cm3 and boron from 1.5 x 10^18/cm3 to 6 x 10^18/cm3, nine samples have luminosities > 70 photons/keV and two have luminosities > 110 photons/keV. Other samples in that range have lower luminosities due to higher concentrations of non-radiative centers. The decay times decrease by typically a factor of ten with increasing free carrier concentrations from 10^17/cm3 to 2 x 10^18/cm3.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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