The impact of the charge barrier height on Germanium (Ge) detectors with amorphous-Ge contacts for light dark matter searches
The impact of the charge barrier height on Germanium (Ge) detectors with amorphous-Ge contacts for light dark matter searches
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DOI：
10.1140/epjc/s10052-020-8029-0
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
Wenzhao Wei;R. Panth;Jing Liu;H. Mei;D. Mei;Guojian Wang
中科院分区：
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作者：
Wenzhao Wei;R. Panth;Jing Liu;H. Mei;D. Mei;Guojian Wang
在寻找低至 MeV 尺度的光暗物质 (LDM) 时，需要能够测量单个电子空穴 (e-h) 对的锗 (Ge) 探测器。我们研究了具有非晶Ge (a-Ge) 触点的Ge 探测器的可行性，以实现测量单个e-h 对的灵敏度，这需要极低的泄漏电流。使用具有 a-Ge 触点的三个 Ge 探测器来研究阻挡电子和空穴的电荷势垒高度。使用测量的体漏电流和德勒-布罗德斯基模型，我们分别获得了顶部和底部接触的电荷势垒高度和费米能级附近的局部能态密度的值。我们预测，在氦气温度 (4 K) 下，体漏电流极小，可以忽略不计。因此，具有 a-Ge 触点的 Ge 探测器具有测量单个 e-h 对以检测 LDM 粒子的潜力。
Germanium (Ge) detectors with ability of measuring a single electron–hole (e–h) pair are needed in searching for light dark matter (LDM) down to the MeV scale. We investigate the feasibility of Ge detectors with amorphous-Ge (a-Ge) contacts to achieve the sensitivity of measuring a single e-h pair, which requires extremely low leakage current. Three Ge detectors with a-Ge contacts are used to study the charge barrier height for blocking electrons and holes. Using the measured bulk leakage current and the Döhler–Brodsky model, we obtain the values for charge barrier height and the density of localized energy states near the Fermi energy level for the top and bottom contacts, respectively. We predict that the bulk leakage current is extremely small and can be neglected at helium temperature (4 K). Thus, Ge detectors with a-Ge contacts possess the potential to measure a single e–h pair for detecting LDM particles.