A versatile instrument for ambient pressure x-ray photoelectron spectroscopy: The Lund cell approach

Abstract

During the past one and a half decades ambient pressure x-ray photoelectron spectroscopy (APXPS) has grown to become a mature technique for the real-time investigation of both solid and liquid surfaces in the presence of a gas or vapour phase. APXPS has been or is being implemented at most major synchrotron radiation facilities and in quite a large number of home laboratories. While most APXPS instruments operate using a standard vacuum chamber as the sample environment, more recently new instruments have been developed which focus on the possibility of custom-designed sample environments with exchangeable ambient pressure cells (AP cells). A particular kind of AP cell solution has been driven by the development of the APXPS instrument for the SPECIES beamline of the MAX IV Laboratory: the solution makes use of a moveable AP cell which for APXPS measurements is docked to the electron energy analyser inside the ultrahigh vacuum instrument. Only the inner volume of the AP cell is filled with gas, while the surrounding vacuum chamber remains under vacuum conditions. The design enables the direct connection of UHV experiments to APXPS experiments, and the swift exchange of AP cells allows different customdesigned sample environments. Moreover, the AP cell design allows the gas-filled inner volume to remain small, which is highly beneficial for experiments in which fast gas exchange is required. Here we report on the design of several AP cells and use a number of cases to exemplify the utility of our approach.

Mobile setup for synchrotron based in situ characterization during thermal and plasma-enhanced atomic layer deposition

“…The conformal nature of ALD tends to result in significant coating of the chamber walls and any detector or other expensive and sensitive parts that are exposed within the vacuum chamber. Therefore, although recently several groups reported exciting data from near ambient pressure XPS, 7,8 traditional UHV-based surface science techniques have been mainly implemented "in vacuo" instead of "in situ" for ALD research so far. For in situ studies, quartz crystal microbalance (QCM), mass spectrometry, and optical characterization techniques such as infrared spectroscopy and spectroscopic ellipsometry (SE) have been most popular.…”

The SPECIES beamline at the MAX IV Laboratory: a facility for soft X-ray RIXS and APXPS

“…The APXPS endstation is described in detail elsewhere (Schnadt et al, 2012;Knudsen et al, 2016) and is discussed here only briefly. The endstation is dedicated to in situ and operando studies of the solid-vapor and liquid-vapor interfaces under ambient-pressure conditions using XPS and NEXAFS using partial and total electron yield detection.…”

UHV and Ambient Pressure XPS: Potentials for Mg, MgO, and Mg(OH)2 Surface Analysis

“…41 There are three basic configurations of APXPS measurement chambers as shown in Fig. 2b, c, and d. 10,12 Exposing a sample to a gas in a standard vacuum chamber is the simplest. These chambers typically have large volumes, and a background pressure of the dosed gas remains after the experiment, necessitating a bake-out to restore UHV.…”

“…A second configuration places the sample in a moveable ambient pressure cell inside a UHV chamber. 12 While this design is more complicated, gases can flow across the sample as opposed to maintaining a static equilibrium. A smaller volume makes for easier cleaning, fast gas exchange, and quick access to UHV and higher pressure conditions.…”

“…The final configuration uses customizable measurement chambers that are easily placed on the EEA. All of these configurations can combine APXPS with simultaneous measurement of other information including mass spectrometry 12 and cyclic voltammetry. 11,42 The most common systems studied using APXPS relate to adsorption and reactions at the solid/gas or vapor phase interface.…”