Sticking coefficients of selenium and tellurium

Abstract

The sticking coefficients of selenium and tellurium were measured as a function of temperature. Molecular beams of the chalcogen elements supplied from thermal effusion cells were directed onto a heated quartz crystal microbalance, and the mass gain rate was detected as a function of temperature. Both sticking coefficients were found to sharply drop within a narrow temperature range of 20 and 30 °C from above 0.8 down to about 0.2 at film surface temperatures around 35 and 115 °C for selenium and tellurium, respectively. While the sticking coefficient of tellurium reached zero at temperatures above 150 °C, the sticking coefficient of selenium remained about 0.2 up to a film surface temperature of 60 °C, suggesting that selenium was supplied in different chemical forms. The direct and quantitative determination of the sticking coefficients provides important insights into the kinetics of chalcogenide-based film growth and points toward the need of a precise sample temperature control.

Growth of Nanometer-Thick γ-InSe on Si(111) 7 × 7 by Molecular Beam Epitaxy for Field-Effect Transistors and Optoelectronic Devices

“…Additionally, the higher flux ratio generally led to thicker films as more Se could incorporate into the film. The direct transition of mixed-phase In 2 Se 3 –InSecategory Ito In-rich InSecategory IIIcan be related to a sharp drop of the Se sticking coefficient, which was reported earlier for pure Se deposition at much lower temperatures. , At even higher temperatures around 400 °C, no film growth was observed on the Si surface, suggesting that both Se and In had a nearly zero sticking coefficient at these growth temperatures.…”

“…The direct transition of mixed-phase In 2 Se 3 − InSe�category I�to In-rich InSe�category III�can be related to a sharp drop of the Se sticking coefficient, which was reported earlier for pure Se deposition at much lower temperatures. 51,52 At even higher temperatures around 400 °C, no film growth was observed on the Si surface, suggesting that both Se and In had a nearly zero sticking coefficient at these growth temperatures. Surface morphologies of single-phase InSe films investigated with AFM are shown in Figure 4.…”

Stoichiometric Growth of Monolayer FeSe Superconducting Films Using a Selenium Cracking Source

“…To obtain the estimation of the actual source flux for the growth, we first calibrate it using a QCM. The QCM head is maintained at room temperature so that the sticking coefficient can be taken as 1 [15]. We choose the Fe flux equivalent to 0.19 layer FeSe per minute (or 5.3 min per layer) and keep it constant in the following experiments.…”

“…Therefore, the Fe atoms landing on the surface are fully sticking, whereas Se has a low sticking coefficient [15]. As for the Se source, most of the documented experiments used ordinary effusion cells or crackers at uncracking temperatures [1,11,16].…”

“…T strate temperate (~400 °C) sits below the evaporating temperatures of Fe and abo of Se [14]. Therefore, the Fe atoms landing on the surface are fully sticking, whe has a low sticking coefficient [15]. As for the Se source, most of the documented ments used ordinary effusion cells or crackers at uncracking temperatures [1,11,1 majority of the thermally evaporated Se species are Se6 and Se5, which are less r than smaller ones [17].…”