Oxygen etching method guides single-crystal growth of 2D semiconductors

A KAIST-led team, with South Korean startup TDS Innovation, published a Nature study on controlling where 2D semiconductor crystals nucleate. Their etching-flux-mediated process uses oxygen from an oxide barrier to suppress random nucleation and encourage one crystal to form at the center of each patterned region. The aim is to reduce grain boundaries that hurt electrical performance and uniformity in future nanoscale devices.

The Nature paper, titled "Spatially deterministic nucleation of 2D semiconductors by etching flux," appeared on October 7. It involved KAIST researchers and South Korean startup TDS Innovation. The team's EF-SCN method relies on oxygen escaping an oxide barrier to create a sideways etching flux. This flux blocks new crystal formation across a patterned area, leaving only the center as a nucleation site.

The work targets transition-metal dichalcogenide monolayers such as MoS₂, which, unlike graphene, possess a band gap. Random nucleation normally yields multiple crystals whose boundaries reduce electrical performance and consistency. In tests, the method produced single crystals at 397 of 400 sites on a two-centimeter substrate. The researchers also fabricated field-effect transistors and measured improved charge-carrier mobility compared with earlier selectively grown MoS₂ devices.

Count: first paragraph: The(1) Nature2 paper3 titled4 "Spatially5 deterministic6 nucleation7 of8 2D9 semiconductors10 by11 etching12 flux,"13 appeared14 on15 October16 7.17 It18 involved19 KAIST20 researchers21 and22 South23 Korean24 startup25 TDS26 Innovation.27 The28 team's29 EF-SCN30 method31 relies32 on33 oxygen34 escaping35 an36 oxide37 barrier38 to39 create40 a41 sideways42 etching43 flux.44 This45 flux46 blocks47 new48 crystal49 formation50 across51 a52 patterned53 area,54 leaving55 only56 the57 center58 as59 a60 nucleation61 site.62

Second: The63 work64 targets65 transition-metal66 dichal