Scanning-probe spectroscopy of semiconductor donor molecules

Abstract

Semiconductor devices continue to press into the nanoscale regime, and new applications have emerged for which the quantum properties of dopant atoms act as the functional part of the device, underscoring the necessity to probe the quantum structure of small numbers of dopant atoms in semiconductors[1-3]. Although dopant properties are well-understood with respect to bulk semiconductors, new questions arise in nanosystems. For example, the quantum energy levels of dopants will be affected by the proximity of nanometer-scale electrodes. Moreover, because shallow donors and acceptors are analogous to hydrogen atoms, experiments on small numbers of dopants have the potential to be a testing ground for fundamental questions of atomic and molecular physics, such as the maximum negative ionization of a molecule with a given number of positive ions[4,5]. Electron tunneling spectroscopy through isolated dopants has been observed in transport studies[6,7]. In addition, Geim and coworkers identified resonances due to two closely spaced donors, effectively forming donor molecules[8]. Here we present capacitance spectroscopy measurements of silicon donors in a gallium-arsenide heterostructure using a scanning probe technique[9,10]. In contrast to the work of Geim et al., our data show discernible peaks attributed to successive electrons entering the molecules. Hence this work represents the first addition spectrum measurement of dopant molecules. More generally, to the best of our knowledge, this study is the first example of single-electron capacitance spectroscopy performed directly with a scanning probe tip[9].

In press, Nature Physics. Original manuscript posted here; 16 pages, 3 figures, 5 supplementary figures

References in corpus (1)

• Transport spectroscopy of a single dopant in a gated silicon nanowire

Cited by in corpus (12)

• Interface roughness, valley-orbit coupling and valley manipulation in quantum dots
• Valley-based noise-resistant quantum computation using Si quantum dots
• Exchange coupling in silicon quantum dots: Theoretical considerations for quantum computation
• Quantum dot spin qubits in Silicon: Multivalley physics
• Microscopic models for charge-noise-induced dephasing of solid-state qubits
• Acoustic Traps and Lattices for Electrons in Semiconductors
• Coherent electrical rotations of valley states in Si quantum dots using the phase of the valley-orbit coupling
• Non-classicality and entanglement criteria for bipartite optical fields characterized by quadratic detectors II: Criteria based on probabilities
• Trionic Optical Potential for Electrons in Semiconductors
• Microcavity polaritons in disordered exciton lattices
• Modeling single- and multiple-electron resonances for electric-field-sensitive scanning probes
• Single-Electron Capacitance Spectroscopy of Individual Dopants in Silicon