Scanning tunneling spectroscopy study of incorporated Al atoms in Si(100) substrate

We have studied the structures and electrical properties of incorporated Al atoms in Si(100) using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) at room temperature in ultra-high vacuum. Our recent work shows that, in Si/Al/Si heterostructures, a hole is a dominant charge carrier and we have achieved a comparable mobilities to previous reports on similar two-dimensional hole gas systems at high charge carrier densities. [1,2] However, the electronic states of Al have not been studied well as dopants in Si. STS can provide the local density of states to understand the electrical properties of incorporated Al atoms in Si(100) similar to the Si/Al/Si heterostructure in our recent work. [1] We will discuss the local density of states measured by STS of incorporated Al atoms in a clean (2x1) reconstructed Si(100) substrate at various densities prepared by thermal Al evaporation and annealing in situ at 550 °C.
[1] AIP Advance 8, 075329 (2018)
[2] Phys. Rev. B 47, 12618 (1993)