Hydrogen desorption from silicane and germanane crystals: Toward creation of free-standing monolayer silicene and germanene

Abstract

We investigate hydrogen desorptions from monolayer and multilayer graphane analogs, namely, silicane (SiH) and germanane (GeH), by the first-principles calculations. It is found from the calculated pressure–temperature diagrams of the monolayer and multilayer SiH and GeH crystals that the hydrogen atoms can be removed by heating and reducing hydrogen partial pressure. We also perform thermal-desorption-spectroscopy measurements for the multilayer crystals in order to demonstrate the validity of the theoretical calculations, and it turns out that the theoretical results are worth believing. Our theoretical results for monolayer SiH/GeH crystals indicate monolayer SiH and GeH crystals possess high potential to find their application as a precursor to free-standing monolayer silicene and germanene, respectively.

SiH monolayer : A promising two‐dimensional thermoelectric material

“…The ZT values of SiX monolayers is nearly equal to 1, which shows that silicon‐based materials are good applicants of thermoelectricity 31,32 . Using first‐principle calculations, M. Araidai et al have investigated the hydrogen desorption from monolayer and multilayer SiH and GeH 33 . D. Cheng et al used SiH for generating SiH/TiO 2 heterojunction for TiO 2 ‐based photocatalyst 34 .…”

“…31,32 Using first-principle calculations, M. Araidai et al have investigated the hydrogen desorption from monolayer and multilayer SiH and GeH. 33 D. Cheng et al used SiH for generating SiH/TiO 2 heterojunction for TiO 2 -based photocatalyst. 34 Motivated by the above work and interesting properties of silicon-based materials, we have systematically investigated structural, stability, electronic and thermoelectric properties of single-layer SiH using first-principle calculations.…”

Crystal structure change in multilayer GeH flakes by hydrogen desorption under ultrahigh vacuum environments

“…The details are summarized in Table Ӏ. In our previous study on thermal desorption spectroscopy (TDS), 21,24) it was revealed that the temperature at which hydrogen desorption is completed is around 300 °C, thus we chose the maximum temperature as 300 °C in the present study. The base pressure was varied from 10 −6 to 10 −3 Pa; the processing time from room temperature (RT) to 300 °C was varied from 35 to 300 min.…”

“…Against this background, we recently proposed a simple method to create free-standing germanene from hydrogenterminated germanane (GeH). 21) According to theoretical calculations, hydrogen atoms could be removed from the GeH surfaces by heating and reducing the hydrogen partial pressure. Several reports of experiments in the thermogravimetric analysis on GeH exist that showed a weight change by thermal heating in an N 2 22) or Ar 23) atmosphere.…”

“…We recently demonstrated hydrogen desorption from GeH by using thermal desorption spectroscopy measurements. 21,24) However, the detailed crystal structures before and after heating have not been clarified. This study investigates gas desorption by thermal heating up to 300 °C from multilayer GeH flakes under different vacuum environments.…”