1 research outputs found
MomentumâSpace Imaging of UltraâThin Electron Liquids in δâDoped Silicon
Abstract Twoâdimensional dopant layers (δâlayers) in semiconductors provide the highâmobility electron liquids (2DELs) needed for nanoscale quantumâelectronic devices. Key parameters such as carrier densities, effective masses, and confinement thicknesses for 2DELs have traditionally been extracted from quantum magnetotransport. In principle, the parameters are immediately readable from the oneâelectron spectral function that can be measured by angleâresolved photoemission spectroscopy (ARPES). Here, buried 2DEL δâlayers in silicon are measured with soft Xâray (SX) ARPES to obtain detailed information about their filled conduction bands and extract deviceârelevant properties. This study takes advantage of the larger probing depth and photon energy range of SXâARPES relative to vacuum ultraviolet (VUV) ARPES to accurately measure the δâlayer electronic confinement. The measurements are made on ambientâexposed samples and yield extremely thin (< 1 nm) and dense (â1014 cmâ2) 2DELs. Critically, this method is used to show that δâlayers of arsenic exhibit better electronic confinement than δâlayers of phosphorus fabricated under identical conditions