Gutzler Rico, Heckl Wolfgang M, Lackinger Markus
Department of Earth and Environmental Sciences and Center for NanoScience (CeNS), Ludwig-Maximilians-University, Theresienstrasse 41, Munich 80333, Germany.
Rev Sci Instrum. 2010 Jan;81(1):015108. doi: 10.1063/1.3292510.
We describe a straightforward, reliable, and inexpensive design of a Knudsen type molecular effusion cell capable of measuring molecular evaporation rates in situ. This is accomplished by means of a quartz crystal microbalance integrated into the shutter of the effusion cell. The presented layout facilitates both the measurement of effusion rates under ultrahigh vacuum conditions without the need for a separate experimental setup and the growth of surface supported molecular layers and nanostructures. As an important prerequisite for reproducible deposition of molecular films with defined coverages ranging from submonolayers up to multilayers, the Knudsen cell features a stable deposition rate for crucible temperatures between 50 and 500 degrees C. Experimental determination of deposition rates for different crucible temperatures allows to approximate sublimation enthalpies of the evaporant based on the Clausius-Clapeyron equation.
我们描述了一种简单、可靠且廉价的克努森型分子泻流池设计，该泻流池能够原位测量分子蒸发速率。这是通过集成在泻流池快门中的石英晶体微天平实现的。所展示的布局既便于在超高真空条件下测量泻流速率，无需单独的实验装置，也便于生长表面支撑的分子层和纳米结构。作为可重复沉积覆盖范围从亚单层到多层的分子膜的重要前提条件，克努森池在坩埚温度为50至500摄氏度之间时具有稳定的沉积速率。通过实验测定不同坩埚温度下的沉积速率，可以根据克劳修斯 - 克拉佩龙方程估算蒸发物的升华焓。
