Energy-Efficient Non-Volatile Photonic Switching via Composition-Engineered Sn-Doped GST
Abstract
Integrated phase-change photonics allows non-volatile optical switching with no static power draw, but the electrical energy needed to reversibly switch the material's state limits practical scaling. Efforts to improve energy efficiency have mostly focused on device optimization, such as redesigning the integrated microheater or waveguide. Here, we take a different, materials-centered approach by alloying Sn to Ge2Sb2Te5 (GST) without altering the device structure or CMOS compatibility. We explore Sn concentrations ranging from 0 at.% to 20 at.% on waveguide-integrated PN and PIN heaters and observe a reduction in both the amorphization and crystallization energies in the 5--10 at.% range. At higher Sn content this trend reverses and the switching energy increases, which is suggestive of phase segregation when combined with TEM compositional analysis. A 10 at.% Sn device continues to switch over 1000 cycles, with observable degradation in the extinction ratio from 4.5 ± 0.3 dB to 2.4 ± 0.3 dB. Post-cycling imaging shows PCM migration and void formation which we believe can be further improved by enhanced encapsulation. Overall, Sn alloying offers a route to lower programming energy in integrated phase-change photonics without negatively affecting the switching speed relative to un-doped GST.
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BibTeX
@misc{zhang2026energyefficient,
title = {{Energy-Efficient Non-Volatile Photonic Switching via Composition-Engineered Sn-Doped GST}},
author = {Xingyu Zhang and Daniel Vaz and Chi-Yi Kao and Marcus Tamura and Xiong Feng and Carlos A. Rios Ocampo and Bhavin J. Shastri and Nathan Youngblood},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.38404},
eprint = {2609.38404},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.38404},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Energy-Efficient Non-Volatile Photonic Switching via Composition-Engineered Sn-Doped GST
AU - Xingyu Zhang
AU - Daniel Vaz
AU - Chi-Yi Kao
AU - Marcus Tamura
AU - Xiong Feng
AU - Carlos A. Rios Ocampo
AU - Bhavin J. Shastri
AU - Nathan Youngblood
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.38404
UR - https://arxiv.org/abs/2609.38404
AB - Integrated phase-change photonics allows non-volatile optical switching with no static power draw, but the electrical energy needed to reversibly switch the material's state limits practical scaling. Efforts to improve energy efficiency have mostly focused on device optimization, such as redesigning the integrated microheater or waveguide. Here, we take a different, materials-centered approach by alloying Sn to Ge_2Sb_2Te_5 (GST) without altering the device structure or CMOS compatibility. We explore Sn concentrations ranging from 0 at.% to 20 at.% on waveguide-integrated PN and PIN heaters and observe a reduction in both the amorphization and crystallization energies in the 5--10 at.% range. At higher Sn content this trend reverses and the switching energy increases, which is suggestive of phase segregation when combined with TEM compositional analysis. A 10 at.% Sn device continues to switch over 1000 cycles, with observable degradation in the extinction ratio from 4.5 ± 0.3 dB to 2.4 ± 0.3 dB. Post-cycling imaging shows PCM migration and void formation which we believe can be further improved by enhanced encapsulation. Overall, Sn alloying offers a route to lower programming energy in integrated phase-change photonics without negatively affecting the switching speed relative to un-doped GST.
ER -