For electronics manufacturing companies that plan to use electrostatic gating and substitutional doping to induce charge carriers in two-dimensional (2D) materials but are dissatisfied with the inability of these methods to produce nonvolatile doping profiles with nanometer resolution. Berkeley Lab’s Local Doping of Two-Dimensional Materials offers a process for locally doping 2D materials at the nanoscale, resulting in patterned configurations.
APPLICATIONS OF TECHNOLOGY:
Controlling the charge density of two-dimensional materials at the nanoscale to:
- Manufacture nonvolatile memory devices
- Fabricate transistors, p-n junctions, and field-programmable gate arrays (FPGAs)
- Improve touchscreen technologies
- Rewritable and erasable patterning allows nanoscale doping configurations in 2D materials
- Has better spatial resolution than many conventional techniques
- Doping is persistent until manually erased, allowing for efficient information storage
- Nanoscale devices can be designed with doped patterns before, during, or after the fabrication process
- Low voltages required by this doping method enable electronic devices to be made reprogrammable by consumers
- Inexpensive and potentially resist-free patterning technique
Two-dimensional (2D) materials (such as graphene and transition metal dichalcogenides) have become promising candidates for fabricating compact electronic and optoelectronic devices. However, the few methods available to induce charge carriers in 2D materials, such as electrostatic gating and substitutional doping, cannot produce nonvolatile doping profiles with nanometer resolution, characteristics needed to control the charge density in small electronic devices.
Berkeley Lab’s Local Doping of Two-Dimensional Materials allows the local nonvolatile doping of 2D materials with nanoscale precision, resulting in patterned configurations. By applying a low voltage pulse to a conductor (such as a metal wire or a carbon nanotube) within a few nanometers of a 2D material, charge carriers are induced in the 2D material in the area near the conductor. This local doping persists in the material after the conductor is removed, and this doping can be altered (and even removed) by subsequent voltage pulses, allowing manufacturers to pattern spatially varying doping configurations in 2D materials used to fabricate nanoscale p-n junctions, sensors, thin-film transistors, memory cells, and optoelectronic circuits, meeting the need for ever-smaller devices.
Berkeley Lab’s local doping technique offers much better spatial resolution for 2D materials than many conventional techniques. For example, because the spatial modulation of the electron density can be patterned with nanoscale precision, small p-n junctions and transistors can be fabricated. The invention also promises to be more efficient than conventional methods. For example, electrostatic gating requires a gate voltage to be on at all times, whereas the Berkeley Lab technique allows the charge carriers to persist even when the gate is turned off. Furthermore, the invention offers unprecedented versatility: With the Berkeley Lab technique, the local doping of a 2D material is reversible and can be removed or erased, whereas this would be impossible with conventional methods such as substitutional doping.
DEVELOPMENT STAGE: Proof of principle.
STATUS: Issued U. S. Patent #9,449,851. Available for licensing or collaborative research.
REFERENCE NUMBER: 2014-097