Realization of solid-state nanothermometer using Ge quantum-dot single-hole transistor in few-hole regime

Semiconductor Ge quantum-dot (QD) thermometry has been demonstrated based on extraordinary temperature-dependent oscillatory differential conductance (G_D) characteristics of Ge-QD single-hole transistors (SHTs) in the few-hole regime. Full-voltage width-at-half-minimum, V_1/2, of G _D valleys appears to be fairly linear in the charge number (n) and temperature within the QD in a relationship of eV_1/2≅ (1- 0.11n) × 5.15k_BT, providing the primary thermometric quantity. The depth of G_D valley is also proportional to charging energy (E _C) and 1/T via ΔG_D≅ E_C/9.18k _BT, providing another thermometric quantity. This experimental demonstration suggests our Ge-QD SHT offering effective building blocks for nanothermometers over a wide temperature range with a detection temperature as high as 155 K in a spatial resolution less than 10 nm and temperature accuracy of sub-kelvin.