Towards superconductivity in p-type delta-doped Si/Al/Si heterostructures

摘要: In pursuit of superconductivity in p-type silicon (Si), we are using a single atomic layer aluminum (Al) sandwiched between Si substrate and thin epi-layer. The delta was fabricated starting from an ultra high vacuum (UHV) flash anneal Si(100) surface, followed by physical vapor deposition Al monolayer. To activate the dopants, sample then annealed in-situ at 550 °C for 1 min. capping electron-beam evaporated room temperature, ex-situ 10 min to recrystallize layer. Low temperature magnetotransport measurements yield maximum hole mobility 20 cm2/V/s carrier density 1.39 × 1014 holes/cm2, which corresponds ≈ (0.93 ± 0.1) holes per dopant atom. No observed these devices even T < 300 mK. Atom probe tomography energy-dispersive X-ray spectroscopy analyses suggest that dopants become distributed over (17 25) nm thickness. Redistribution reduces concentration matrix below critical observe superconductivity.