Tunable and Transferable Diamond Membranes for Integrated Quantum Technologies

TL;DR

This paper presents the development of tunable, transferable diamond membranes with embedded color centers, enabling improved integration of diamond-based qubits into quantum devices with enhanced coherence properties.

Contribution

It introduces a method to synthesize uniform, tunable, and transferable diamond membranes with embedded color centers, advancing integration in quantum technologies.

Findings

Membranes have tunable thicknesses from 50 to 250 nm.

Embedded GeV and NV centers exhibit stable photoluminescence and long coherence times.

Membranes are atomically flat and maintain bulk-diamond-like crystallinity.

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 nm 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 linewidths 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 us and 400 us, respectively. This platform enables the straightforward integration of diamond membranes that host coherent color centers into quantum technologies.