论文标题
快速低噪声透明放大器用于扫描隧道显微镜及以后
Fast low-noise transimpedance amplifier for scanning tunneling microscopy and beyond
论文作者
论文摘要
已设计用于扫描隧道显微镜（STM）的变速器放大器。该放大器具有低噪声（受低输入电流和低频率下的1GΩ反馈电阻的约翰逊噪声的限制），对于大多数STM应用（35 pf输入电容的50 kHz），足够的带宽，一个较大的动态范围（0.1 PA-50 NA，无范围开关），以及低输入Voltip foltiptage foltage offtage offetage offet ables。该放大器还适用于将其第一阶段放入低温STM的低温恒温器中，从而最大程度地减少输入电容并降低反馈电阻器的Johnson噪声。放大器还可以找到用于扫描电子显微镜中的样品电流成像和电子光束诱导的电流测量值的应用，并作为具有较大动态范围的光电二极管放大器。本文还讨论了噪声的来源，包括操作放大器的非平衡输入阻抗的经常被忽略的效果，并描述了如何准确测量和调整低流动透射率放大器的频率响应。
A transimpedance amplifier has been designed for scanning tunneling microscopy (STM). The amplifier features low noise (limited by the Johnson noise of the 1 GΩ feedback resistor at low input current and low frequencies), sufficient bandwidth for most STM applications (50 kHz at 35 pF input capacitance), a large dynamic range (0.1 pA--50 nA without range switching), and a low input voltage offset. The amplifier is also suited for placing its first stage into the cryostat of a low-temperature STM, minimizing the input capacitance and reducing the Johnson noise of the feedback resistor. The amplifier may also find applications for specimen current imaging and electron-beam-induced current measurements in scanning electron microscopy and as a photodiode amplifier with a large dynamic range. This paper also discusses the sources of noise including the often neglected effect of non-balanced input impedance of operational amplifiers and describes how to accurately measure and adjust the frequency response of low-current transimpedance amplifiers.
