We demonstrate that individual electron-hole pairs are resolved in a 1 cm2 by 4 mm thick silicon crystal (0.93 g) operated at ∼35 mK. One side of the detector is patterned with two quasiparticle-trap-assisted electro-thermal-feedback transition edge sensor (QET) arrays held near ground potential. The other side contains a bias grid with 20\% coverage. Bias potentials up to ± 160 V were used in the work reported here. A fiber optic provides 650~nm (1.9 eV) photons that each produce an electron-hole (e−h+) pair in the crystal near the grid. The energy of the drifting charges is measured with a phonon sensor noise σ∼0.09 e−h+ pair. The observed charge quantization is nearly identical for h+'s or e−'s transported across the crystal.
@article{arxiv.1710.09335,
title = {Thermal detection of single e-h pairs in a biased silicon crystal detector},
author = {R. K. Romani and P. L. Brink and B. Cabrera and M. Cherry and T. Howarth and N. Kurinsky and R. A. Moffatt and R. Partridge and F. Ponce and M. Pyle and A. Tomada and S. Yellin and J. J. Yen and B. A. Young},
journal= {arXiv preprint arXiv:1710.09335},
year = {2018}
}