摘要
基于扫描隧道显微镜的新型纳米阻抗显微镜(STM-NIM)能够测量材料表面的纳米微区阻抗性质并具有分辨率高的突出优点,但传统STM前置放大器的频率带宽不能满足STM-NIM测量模式的要求,因而需要设计新型前置放大器。STM-NIM前置放大器必须在噪声和频率带宽两方面同时具有非常优良的性能。本文利用STM及NIM信号的特点,通过将信号一分为二并对电路进行优化,研制出了满足STM-NIM测量要求的新型前置放大器。测试表明,该前置放大器能同时用于NIM阻抗测量和STM形貌扫描;其NIM信号的频率带宽达到300 kHz;其STM信号的噪声约为0．8 mV,能满足原子级分辨成像的要求。
Nano impedance microscope based on scanning tunneling microscope （STM-NIM） can measure local surface impedance on nano scale. Because the frequency bandwidth of conventional STM preamplifier is not wide enough for STM-NIM, it becomes a key point to design a new preamplifier with excellent performances both in noise and frequency bandwidth. By making use of the features of STM and NIM signals, dividing the signal into two parts, and optimizing the circuits respectively, a novel preamplifier that suits STM-NIM measurement was realized. Experimental tests indicate that the preamplifier can be used for STM topography measurement and NIM impedance measurement simultaneously. The NIM signal frequency bandwidth of this preamplifier is up to 300 kHz, while the STM signal noise is about 0.8 mV, which meets atomic resolution imaging requirement.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2007年第1期57-61,共5页
Chinese Journal of Scientific Instrument
基金
广东省项目(01-09080-4202372
2005A10703001)
广州市攻关项目(200322-D2021
20136Z3-D2071)资助项目
关键词
扫描隧道显微镜
纳米阻抗显微镜
前置放大器
噪声
带宽
scanning tunneling microscope （ STM ）
nano impedance microscopy （ NIM ）
preamplifier
noise
bandwidth
