Abstract

Researchers working with thin samples, such as monolayer graphene, are consistently struggling against contamination. Indeed, the problem of hydrocarbon contamination has been known from the earliest days of electron microscopy and efforts to reduce this problem are ubiquitous to almost all high-vacuum experiments. Accurate knowledge of the behavior of such contamination is essential for electron beam (e-beam) based atomic fabrication, where we aspire to select and control matter on an atom-by-atom basis. Here, we take up the vexing question of hydrocarbon contamination on graphene. Image intensity is used to directly reveal the presence of diffusing hydrocarbons on ostensibly clean graphene. These diffusing hydrocarbons have been previously inferred but not directly observed. Surprising dynamic variations of the concentration of these hydrocarbons impels questions about their origin. Here we present some possible explanations and draw some tentative conclusions. This work updates the conceptual model of ‘clean graphene’ and offers refinements to the description of e-beam induced hydrocarbon deposition.

Abstract

Researchers working with thin samples, such as monolayer graphene, are consistently struggling against contamination. Indeed, the problem of hydrocarbon contamination has been known from the earliest days of electron microscopy and efforts to reduce this problem are ubiquitous to almost all high-vacuum experiments. Accurate knowledge of the behavior of such contamination is essential for electron beam (e-beam) based atomic fabrication, where we aspire to select and control matter on an atom-by-atom basis. Here, we take up the vexing question of hydrocarbon contamination on graphene. Image intensity is used to directly reveal the presence of diffusing hydrocarbons on ostensibly clean graphene. These diffusing hydrocarbons have been previously inferred but not directly observed. Surprising dynamic variations of the concentration of these hydrocarbons impels questions about their origin. Here we present some possible explanations and draw some tentative conclusions. This work updates the conceptual model of ‘clean graphene’ and offers refinements to the description of e-beam induced hydrocarbon deposition.

Abstract

Researchers working with thin samples, such as monolayer graphene, are consistently struggling against contamination. Indeed, the problem of hydrocarbon contamination has been known from the earliest days of electron microscopy and efforts to reduce this problem are ubiquitous to almost all high-vacuum experiments. Accurate knowledge of the behavior of such contamination is essential for electron beam (e-beam) based atomic fabrication, where we aspire to select and control matter on an atom-by-atom basis. Here, we take up the vexing question of hydrocarbon contamination on graphene. Image intensity is used to directly reveal the presence of diffusing hydrocarbons on ostensibly clean graphene. These diffusing hydrocarbons have been previously inferred but not directly observed. Surprising dynamic variations of the concentration of these hydrocarbons impels questions about their origin. Here we present some possible explanations and draw some tentative conclusions. This work updates the conceptual model of ‘clean graphene’ and offers refinements to the description of e-beam induced hydrocarbon deposition.

Abstract

Researchers working with thin samples, such as monolayer graphene, are consistently struggling against contamination. Indeed, the problem of hydrocarbon contamination has been known from the earliest days of electron microscopy and efforts to reduce this problem are ubiquitous to almost all high-vacuum experiments. Accurate knowledge of the behavior of such contamination is essential for electron beam (e-beam) based atomic fabrication, where we aspire to select and control matter on an atom-by-atom basis. Here, we take up the vexing question of hydrocarbon contamination on graphene. Image intensity is used to directly reveal the presence of diffusing hydrocarbons on ostensibly clean graphene. These diffusing hydrocarbons have been previously inferred but not directly observed. Surprising dynamic variations of the concentration of these hydrocarbons impels questions about their origin. Here we present some possible explanations and draw some tentative conclusions. This work updates the conceptual model of ‘clean graphene’ and offers refinements to the description of e-beam induced hydrocarbon deposition.