Thermal activation of valley-orbit states of neutral magnesium in silicon

TL;DR

This study investigates the thermal activation of valley-orbit states in neutral magnesium-doped silicon, revealing temperature-dependent transitions and providing insights into the energy levels of magnesium donors.

Contribution

It reports the first observation of thermal activation from the ground state to valley-orbit states in magnesium-doped silicon through absorption measurements.

Findings

Thermal activation from 1sA to valley-orbit states observed.

Transitions from thermally populated levels to odd-parity states identified.

Provides energy level data for magnesium donor states in silicon.

Abstract

Interstitial magnesium acts as a moderately deep double donor in silicon, and is relatively easily introduced by diffusion. Unlike the case of the chalcogen double donors, the binding energies of the even-parity valley-orbit excited states 1sT$_2$ and 1sE have remained elusive. Here we report on temperature dependence absorption measurements focusing on the neutral charge species. Our results demonstrate thermal activation from the ground state 1sA to the valley-orbit states, as observed by transitions from the thermally populated levels to the odd-parity states 2p$_0$ and 2p$_{\pm}$