Multistage ballistic rectifiers on Si/SiGe hetreostructures

Si/SiGe 异质结构上的多级弹道整流器

• 批准号: 397194044
• 负责人: Professor Dr. Joachim Knoch, since 7/2021
• 金额: --
• 依托单位: Institut für Halbleitertechnik (IHT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/397194044?language=en
• 关键词: Multistage; ballistic; rectifiers; Si; SiGe

Multistage ballistic rectifiers are prepared on modulation-doped Si/SiGe heterostructures. Their single stages consist of asymmetric nanoscale cross junctions, which exhibit a parabolic output-voltage-vs-input-current characteristic. Accordingly, the polarity of the output voltage is independent of that of the input current. The mechanism of this full-wave rectification relies upon a stationary charging of the current-free voltage channel over the distance of the momentum relaxation length (MRL), if the MRL is larger than the lateral dimension of the cross junction. Since the output voltage of a single stage only reaches a few mV, many rectifier stages are necessary for technical applications. In the present project, we exploit the recently published effect of input-current addition, which arises if the stage separation is smaller than the MRL, and which in dual-stage rectifiers causes a synergy gain in the output voltage of a factor of two due to the parabolic transfer characteristic. Therefore, the rectifier stages are positioned as close as possible. At first, the rectifier efficiency of the single stages is determined at low temperatures by measurements in the nonlinear transport regime. As assumed from studying densely positioned dual-stage ballistic rectifiers, the efficiency of the single rectifier stages is worsened by mutual disturbing of the potential landscape defining the asymmetric cross junctions. This problem is to be solved as far as possible by an improved geometry. Accordingly optimized multiple-stage rectifiers are studied regarding their current-addition effects in a temperature range from 4 K to 120 K. Finally, the number of stages will be determined which is necessary to achieve an output voltage approaching the input voltage. Appropriately prepared multi-stage rectifiers will be characterised with respect to parameters which are relevant for their use as technical device.

在调制掺杂的Si/SiGe异质结上制备了多级弹道整流器。它们的单级由不对称的纳米级交叉结组成，表现出输出电压与输入电流的抛物线特性。因此，输出电压的极性与输入电流的极性无关。如果动量弛豫长度(MRL)大于交叉结的横向尺寸，则这种全波整流的机制依赖于无电流电压通道在动量弛豫长度(MRL)距离上的稳定充电。由于单级输出电压只有几mV，因此在技术应用中需要多个整流级。在本项目中，我们利用了最近发表的输入电流相加效应，该效应在级间隔小于MRL时出现，在双级整流器中，由于抛物线传输特性，导致输出电压的协同增益为原来的两倍。因此，整流级的位置尽可能靠近。首先，通过在非线性输运区域的测量，确定了单级在低温下的整流效率。根据对密集布置的双级弹道整流器的研究，假设单级整流器级的效率因定义非对称交叉点的势能环境的相互干扰而恶化。这个问题将通过改进几何结构来尽可能地解决。在4K到120K的温度范围内，研究了优化的多级整流器的电流附加效应。最后，确定了使输出电压接近输入电压所需的级数。适当准备的多级整流器将根据与其作为技术装置的使用相关的参数来确定其特征。