Epitaxial nucleation and lateral growth of high-crystalline black phosphorus films on silicon

Abstract

Black phosphorus (BP) is a promising two-dimensional layered semiconductor material for next-generation electronics and optoelectronics, with a thickness-dependent tunable direct bandgap and high carrier mobility. Though great research advantages have been achieved on BP, lateral synthesis of high quality BP films still remains a great challenge. Here, we report the direct growth of large-scale crystalline BP films on insulating silicon substrates by a gasphase growth strategy with an epitaxial nucleation design and a further lateral growth control. The optimized lateral size of the achieved BP films can reach up to millimeters, with the ability to modulate thickness from a few to hundreds of nanometers. The as-grown BP films exhibit excellent electrical properties, with a field-effect and Hall mobility of over 1200 cm 2 V −1 s −1 and 1400 cm 2 V −1 s −1 at room temperature, respectively, comparable to those exfoliated from BP bulk crystals. Our work opens the door for broad applications with BP in scalable electronic and optoelectronic devices.

Synthesis Techniques, Optoelectronic Properties, and Broadband Photodetection of Thin‐Film Black Phosphorus

“…In this section, we give a sketchy introduction about the synthesis techniques of thin‐film BP, including micromechanical exfoliation, [ 28,32,105–109 ] liquid‐phase exfoliation, [ 110–134 ] electrochemical exfoliation, [ 135–138 ] alkali metal intercalation, [ 139 ] plasma etching, [ 140–144 ] thermal sublimation, [ 145,146 ] anodic oxidation, [ 147 ] chemical thinning method, [ 148 ] mechanochemical method, [ 149 ] red phosphorus (RP)‐to‐BP conversion, [ 150–153 ] pulsed laser deposition, [ 154,155 ] solvothermal method, [ 156,157 ] and lateral growth method. [ 158 ] All these methods can be categorized into “top‐down” and “bottom‐up” techniques.…”

“…(b, d) Reproduced under the terms of a Creative Commons CC‐BY license. [ 158 ] Copyright 2020, Springer Nature.…”

“…Recently, Xu et al reported the technique of epitaxial nucleation and lateral growth of high‐crystalline thin‐film BP on SiO 2 /Si substrate, using Au 3 SnP 7 as nucleation seeds. [ 158 ] As shown in Figure 2b, at high temperature of 750 °C, Au 3 SnP 7 is formed on the surface of wafer when excessive RP and Sn react with the Au coating on Si/SiO 2 substrate. [ 158 ] Then, with temperature decreasing, P 4 vapor would condense and precipitate onto the surface of Au 3 SnP 7 , leading to epitaxial growth of BP along the (010) plane of Au 3 SnP 7 .…”

“…[ 158 ] As shown in Figure 2b, at high temperature of 750 °C, Au 3 SnP 7 is formed on the surface of wafer when excessive RP and Sn react with the Au coating on Si/SiO 2 substrate. [ 158 ] Then, with temperature decreasing, P 4 vapor would condense and precipitate onto the surface of Au 3 SnP 7 , leading to epitaxial growth of BP along the (010) plane of Au 3 SnP 7 . [ 158 ] Small BP nanosheets would gradually fuse across with each other and finally form a large‐area flake.…”

“…[ 158 ] Then, with temperature decreasing, P 4 vapor would condense and precipitate onto the surface of Au 3 SnP 7 , leading to epitaxial growth of BP along the (010) plane of Au 3 SnP 7 . [ 158 ] Small BP nanosheets would gradually fuse across with each other and finally form a large‐area flake. The lateral size and thickness can be controlled by adjusting the temperature gradient between P 4 source (low temperature side) and vertically stacked substrates (high temperature side).…”