Low temperature ultrahigh vacuum scanning tunneling microscope GPI CRYO


The device is designed for high-precision (atomic scale) study of processes occurring on metal and semiconductor surfaces in the 5-300 K temperature range under ultrahigh or extremely high vacuum. The device makes it possible to record atomic resolution topograms, electron spectra of clean surfaces, adsorbed layers and single objects (atoms, molecules, clusters), and vibrational spectra of single molecules in the regime of inelastic electron tunneling (IETS). The device can be integrated into any analytical or technological vacuum unit.

Unique Features

 Capability to deliver gas, molecular and light (laser) beams directly onto the sample into the zone of a tunnel junction during the scanning process.
 High stability. The drift of the tip relative to the sample is 0.03 nm per hour at 5 K and less than 0.5 nm per hour at 77 K in all three coordinates.
 Low noise control electronics and high vibroinsulation. The tip-sample gap deviation is less than 2 pm.
 Tip positioning in X, Y, Z coordinates in the range of 6×6×3 mm.
 Not less than 60 hours of continuous operation at 5 K on a single liquid helium and 300 hours at 77 K on a single liquid nitrogen refill. Cryostat radiation shields are cooled by coolant evaporation, which eliminates the need for an external nitrogen cryostat.


View from the central window



View from the right window


Технические характеристики 

Диапазон рабочих температур   5 ÷ 300 К
Стандартные опции   топография, спектроскопия
Максимальная область сканирования (X,Y,Z)   Т = 5 К - 2.2х2.2х0.56 мкм
    Т = 300 К - 8.0х8.0х2.0 мкм
Минимальный шаг при сканировании (X,Y,Z)   0,001 нм
Область позиционирования (X,Y,Z)   6х6х3 мм
Точность измерения межатомных расстояний   0.1 нм
Пространственное разрешение   атомное разрешение на металлах
Туннельная спектроскопия, чувствительность   0.1 нА/В
Механизм подвода и позиционирования   пьезо-инерционный
Диапазон туннельного тока   10 пА - 50.0 нА
Резонансная частота сканера   7 кГц
Тип обратной связи   цифровая, ADSP 2181
Размер образца (X,Y,Z)   10x10x2 мм
Базовое давление в вакуумной камере   2x10-11 Торр
Криостат   2.9 л, без азотной рубашки
Длительность работы при 5 К на одной заливке гелия   64 часа
Расход гелия   < 50 мл/час
Максимальная температура прогрева при отжиге вакуумной камеры   160 С


Vacuum module design

The basis of the vacuum module is a nitrogen-free helium cryostat with a 2.9 liter tank and an STM scanning head beneath it. The cryostat and the STM are wrapped in three gold-plated copper radiation shields. The internal shield with holes and a rotating shutter is attached tightly to the helium tank, while the intermediate and outer ones are mechanically fastened to the appropriate heat exchangers, cooled with helium evaporating from the cryostat. The STM scanning head is suspended on four springs with a resonant frequency of 2.5 Hz. Eddy current head damping is done by four samarium-cobalt magnets at the bottom of the STM. Feedthroughs for the scanning head arrester and electrical wires are located on top of the bearing CF200 flange. Samples and tips are changed, and the shutters of all three shields manipulated with a universal mechanical arm.



The compact axisymmetric design of the scanner head reduces thermal drifts and increases mechanical resonant frequency. The head consists of a central XYZ scanner piezoelectric tube with a tip holder fixed on top and a vertical slider driven by other six tubes with an XY positioner and a sample stage on it. The sample holder (usually Omicron standard) is mounted on the sample stage equipped with a heater and a temperature gauge, which can be installed on top of the slider or onto a special adapter for pre-cooling. Scanner arresting is done by lifting the head and pressing it upon a supporting ring. The tip and sample positions can be reversed.

Результаты тестов и измерений 




Powered by Free Joomla Templates & Joomla Hosting provided by AT&T Upgrades and Wireless Keyboards