Tunable and Transferable Diamond Membranes for Integrated Quantum Technologies.

Xinghan Guo,Nazar Delegan,Jonathan C Karsch,Amy Butcher,Alexander A High,Tianle Liu,Zixi Li,David D Awschalom,F Joseph Heremans,Robert Shreiner

doi:10.1021/acs.nanolett.1c03703

Abstract

Color centers in diamond are widely explored as qubits in quantum technologies. However, challenges remain in the effective and efficient integration of these diamond-hosted qubits in device heterostructures. Here, nanoscale-thick uniform diamond membranes are synthesized via “smart-cut” and isotopically (12C) purified overgrowth. These membranes have tunable thicknesses (demonstrated 50 to 250 nm), are deterministically transferable, have bilaterally atomically flat surfaces (Rq ≤ 0.3 nm), and bulk-diamond-like crystallinity. Color centers are synthesized via both implantation and in situ overgrowth incorporation. Within 110-nm-thick membranes, individual germanium-vacancy (GeV–) centers exhibit stable photoluminescence at 5.4 K and average optical transition line widths as low as 125 MHz. The room temperature spin coherence of individual nitrogen-vacancy (NV–) centers shows Ramsey spin dephasing times (T2*) and Hahn echo times (T2) as long as 150 and 400 μs, respectively. This platform enables the straightforward integration of diamond membranes that host coherent color centers into quantum technologies.

Highlights

Color centers in diamond are widely explored as qubits in quantum technologies
While strain was generated from the membrane mounting, thermal expansion ratio mismatch with the carrier wafer, and hydrogen silsesquioxane (HSQ) annealing may potentially contribute to energetic variation, our measurements indicate that the crystal environments between the diamond membrane and the bulk diamond are highly similar
We have demonstrated that color centers within the membranes have sufficient optical and spin coherence for a broad range of applications in quantum information science (QIS)

Summary

Introduction

Color centers in diamond are widely explored as qubits in quantum technologies. challenges remain in the effective and efficient integration of these diamond-hosted qubits in device heterostructures. To realize a fully integrable diamond platform, we have engineered a high-yield, controllable process to lithographically pattern arbitrarily shaped membranes into the overgrown films and subsequently transfer them onto other substrates/devices.

Results

Conclusion