Performance Improvement in Hydrogenated Few-Layer Black Phosphorus Field-Effect Transistors

Abstract

A capping layer for black phosphorus (BP) field-effect transistors (FETs) can provide effective isolation from the ambient air; however, this also brings inconvenience to the post-treatment for optimizing devices. We perform low-temperature hydrogenation on Al2O3 capped BP FETs. The hydrogenated BP devices exhibit a pronounced improvement of mobility from 69.6 to 107.7 cm2v−1s−1, and a dramatic decrease of subthreshold swing from 8.4 to 2.6 V/dec. Furthermore, high/low frequency capacitance–voltage measurements suggest reduced interface defects in hydrogenated BP FETs. This could be due to the passivation of interface traps at both Al2O3/BP and BP/SiO2 interfaces with hydrogen revealed by secondary ion mass spectroscopy.

Anisotropic Band Evolution of Bulk Black Phosphorus Induced by Uniaxial Tensile Strain

“…The exceptional electrical properties of black phosphorus (BP) are exemplified by its significantly high electron mobility [1,2] and high on/off ratio of up to 10 5 in transistor applications. [3][4][5][6] In the field of optoelectronics, the direct bandgap of BP can be regulated over a wide range (0.3-2.0 eV) via band engineering, [7][8][9][10][11][12][13] and results in effective coupling with various optical wavelengths. The layered BP also demonstrates impressive mechanical resilience, with a critical tensile strain of up to 32% in theory.…”