Expanded InSe Crystal Structure with Reduced Intrinsic Defects for High-Performance Field-Effect Transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Intrinsic defects significantly impact the performance of Indium Selenide (InSe)-based Field-Effect Transistors (FETs).
• Controlling these defects is crucial for developing advanced electronic and optoelectronic devices.

Purpose of the Study:

• To investigate the effect of space growth on InSe crystal structure and defect density.
• To develop high-performance InSe FETs by leveraging reduced intrinsic defects.

Main Methods:

• Space growth of InSe on the China Space Station.
• Spherical aberration corrected transmission electron microscopy (TEM) for lattice analysis.
• Density functional theory (DFT) calculations for defect energy and electronic properties.

Main Results:

• Space-grown InSe showed lattice expansion (1.29% intralayer, 3.65% interlayer) and increased defect generation energy, enhancing lattice integrity.
• Unique electronic properties observed in space-grown InSe, including a narrower bandgap and reduced electron effective mass.
• Space InSe FETs demonstrated superior electrical characteristics (I_on: 6.0 µA µm^-1, on/off ratio: 10⁸, V_hys: 0.6 V) and photoelectrical performance (Responsivity: 5316 A W^-1, Detectivity: 1.38 × 10¹² Jones) compared to ground-grown counterparts.

Conclusions:

• Space growth effectively reduces intrinsic defects in InSe, leading to improved crystal quality and lattice integrity.
• The modified electronic properties of space-grown InSe facilitate enhanced electron transport and device performance.
• This research offers insights into crystal structure manipulation for advancing high-performance 2D FETs.