基于ZnSe的场效应晶体管在低温下的实现，作为未来自旋量子比特应用的平台
Realization of ZnSe-based Field-Effect Transistors operating at Cryogenic Temperatures as a Platform for Future Spin-Qubit Applications
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中文总结 AI 辅助
本研究利用阴影墙技术和原位Al欧姆接触实现了基于ZnSe的常关型场效应晶体管，在低温下表现出有效栅控和高迁移率，为未来自旋量子比特应用提供了平台。
中文摘要 AI 辅助
宽禁带化合物半导体ZnSe是实现电子自旋量子比特的有前景的宿主材料。其非简并导带和同位素核自旋纯化的潜力预示着长的自旋相干时间。此类器件的关键要求包括对ZnSe中电子的可靠静电控制以及在低温下保持功能的低电阻欧姆接触。在本工作中，我们利用一种新颖的分子束外延阴影墙技术，结合原位沉积的Al欧姆接触，实现了基于ZnSe的常关型场效应晶体管。这些器件在从室温降至5 K的温度范围内表现出线性的输出特性和有效的沟道栅控，证实了对未掺杂ZnSe沟道的低电阻欧姆接触。通过静电栅控，漏极电流可以被调制几个数量级，在所研究的温度范围内阈值电压约为3 V，场效应迁移率超过100 cm²/Vs。自洽的薛定谔-泊松和漂移-扩散模拟再现了所测得的转移特性，并提供了对界面静电学在决定沟道形成和阈值电压中作用的见解。这些结果展示了栅控ZnSe异质结构在未来自旋量子比特应用中的潜力。
英文摘要
The wide-bandgap compound semiconductor ZnSe is a promising host material for the realization of electron spin-qubits. Its non-degenerate conduction band and the potential for isotopic nuclear spin purification promise long spin coherence times. Key requirements for such devices include reliable electrostatic control of electrons in ZnSe and low-resistance ohmic contacts that remain functional at cryogenic temperatures. In this work, we utilize a novel Shadow Wall technique for molecular-beam epitaxy combined with in-situ deposition of Al ohmic contacts to realize normally-off ZnSe-based field-effect transistors. The devices exhibit linear output characteristics and effective gate control of the channel from room temperature down to 5 K, confirming low-resistance ohmic contacts to the undoped ZnSe channel. The drain current can be modulated by several orders of magnitude through electrostatic gating, with threshold voltages of approximately 3 V and field-effect mobilities exceeding 100 cm2/Vs over the investigated temperature range. Self-consistent Schrödinger-Poisson and drift-diffusion simulations reproduce the measured transfer characteristics and provide insight into the role of interface electrostatics in determining the channel formation and threshold voltage. These results demonstrate the potential of gated ZnSe heterostructures for future spin-qubit applications.
