Quantum Size Effects on the Chemical Sensing Performance of Two-Dimensional Semiconductors

We investigate the role of quantum confinement on the performance of gas sensors based on two-dimensional InAs membranes. Pd-decorated InAs membranes configured as H₂ sensors are shown to exhibit strong thickness dependence, with ∼100× enhancement in the sensor response as the thickness is reduced from 48 to 8 nm. Through detailed experiments and modeling, the thickness scaling trend is attributed to the quantization of electrons which favorably alters both the position and the transport properties of charge carriers; thus making them more susceptible to surface phenomena

Self-Aligned, Extremely High Frequency III–V Metal-Oxide-Semiconductor Field-Effect Transistors on Rigid and Flexible Substrates

This paper reports the radio frequency (RF) performance of InAs nanomembrane transistors on both mechanically rigid and flexible substrates. We have employed a self-aligned device architecture by using a T-shaped gate structure to fabricate high performance InAs metal-oxide-semiconductor field-effect transistors (MOSFETs) with channel lengths down to 75 nm. RF measurements reveal that the InAs devices made on a silicon substrate exhibit a cutoff frequency (<i>f</i>_t) of ∼165 GHz, which is one of the best results achieved in III–V MOSFETs on silicon. Similarly, the devices fabricated on a bendable polyimide substrate provide a <i>f</i>_t of ∼105 GHz, representing the best performance achieved for transistors fabricated directly on mechanically flexible substrates. The results demonstrate the potential of III–V-on-insulator platform for extremely high-frequency (EHF) electronics on both conventional silicon and flexible substrates

Nanoscale InGaSb Heterostructure Membranes on Si Substrates for High Hole Mobility Transistors

As of yet, III–V p-type field-effect transistors (p-FETs) on Si have not been reported, due partly to materials and processing challenges, presenting an important bottleneck in the development of complementary III–V electronics. Here, we report the first high-mobility III–V p-FET on Si, enabled by the epitaxial layer transfer of InGaSb heterostructures with nanoscale thicknesses. Importantly, the use of ultrathin (thickness, ∼2.5 nm) InAs cladding layers results in drastic performance enhancements arising from (i) surface passivation of the InGaSb channel, (ii) mobility enhancement due to the confinement of holes in InGaSb, and (iii) low-resistance, dopant-free contacts due to the type III band alignment of the heterojunction. The fabricated p-FETs display a peak effective mobility of ∼820 cm²/(V s) for holes with a subthreshold swing of ∼130 mV/decade. The results present an important advance in the field of III–V electronics