Wafer‐Scale Growth of Aligned C₆₀ Single Crystals via Solution‐Phase Epitaxy for High‐Performance Transistors

Abstract

Fullerene (C 60 ) single crystals with exceptionally low defects and nearly perfect translational symmetry make them appealing in achieving high-performance n-type organic transistors. However, because of its natural 0D structure, control over continuous crystallization of C 60 over a large area is extremely challenging. Here, the authors report a solution-phase epitaxial approach for wafer-scale growth of continuously aligned C 60 single crystals. This method enables the rational control of the density of nucleation event at meniscus front by confining the size and shape of meniscus with a microchannel template. In this case, a single nucleus as seed crystal can be formed at the front of meniscus, and then epitaxial growth from the seed crystal occurs with continuous retreat of the meniscus. As a result, highly uniform C 60 singlecrystal array with ultralow defect density is obtained on 2-inch substrate. Organic field-effect transistors made from the C 60 single-crystal array show a high average electron mobility of 2.17 cm 2 V −1 s −1 , along with a maximum mobility of 5.09 cm 2 V −1 s −1 , which is much superior to the C 60 polycrystalline film-based devices. This strategy opens new opportunities for the scalable fabrication of high-performance integrated devices based on organic crystals.

Enhancing the Uniformity of Organic Field‐Effect Transistors by a Single‐Crystalline Layer‐Controlled Active Channel

“…One of the main reasons is that the uniformity of OFETs urgently needs improvement to fulfill the requirements of medium‐to‐large scale integrated circuits. [ 22 ] Being a key figure of merit to evaluate the uniformity, the coefficient of variance (CV) in reported OFETs mostly falls in the range of 8–50%, [ 23–39 ] which is not comparable with silicon‐based integrated circuits. Very recently, Deng et al.…”

“…One of the main reasons is that the uniformity of OFETs urgently needs improvement to fulfill the requirements of medium-tolarge scale integrated circuits. [22] Being a key figure of merit to evaluate the uniformity, the coefficient of variance (CV) in reported OFETs mostly falls in the range of 8-50%, [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] which is not comparable with silicon-based integrated circuits. Very recently, Deng et al combined nucleation selection and template growth methods to grow uni-oriented single-crystal arrays, which exhibited CV in mobility of 7.8%.…”

Direct laser patterning of organic semiconductors for high performance OFET-based gas sensors

“…[6][7][8] To obtain high-performance organic circuitry, a key point is the realization of patterned and orderly aligned OSC arrays which ensures minimal leakage current, low cross-talk between devices and a high integration level. 4,[9][10][11][12][13][14][15][16][17][18][19][20][21] By taking advantage of either the modulation of the wettability of the substrate or meniscusguided growth technique, a plethora of approaches, including dip-coating, 20 solution-shearing, 16,17 mold stamping, 12,13 and capillary-confinement crystallization, 18,19 have been reported to create polymeric/molecular OSC patterns with specific orientation, superior uniformity and extreme high device density. In addition to these template-assisted bottom-up approaches, microlithography also has emerged as a powerful tool in patterning organic semiconductors.…”

Scalable Growth of Organic Single‐Crystal Films via an Orientation Filter Funnel for High‐Performance Transistors with Excellent Uniformity

“…However, pervious investigations are predominantly based on organic bulk crystals or small-sized organic micro/ nanocrystals. Although they are promising to explore the fundamental physical properties of organic semiconductors and develop proof-of-concept devices, [5,10,[12][13][14][15] the limited size, discrete spatial distribution, random orientation, and nonuniform morphologies and structures pose a great challenge to the fabrication of large-area, integrated organic single-crystal circuits for practical applications.Organic single-crystal films (OSCFs), in analogy to inorganic single-crystal wafers, have the merits of large-area uniformity, few defects, and lack of grain boundaries, which are ideal platform to harness the extraordinary properties of organic single crystals for novel applications. Nevertheless, growth of largescale OSCFs on scalable substrate has not been well demonstrated so far.…”

“…However, pervious investigations are predominantly based on organic bulk crystals or small-sized organic micro/ nanocrystals. Although they are promising to explore the fundamental physical properties of organic semiconductors and develop proof-of-concept devices, [5,10,[12][13][14][15] the limited size, discrete spatial distribution, random orientation, and nonuniform morphologies and structures pose a great challenge to the fabrication of large-area, integrated organic single-crystal circuits for practical applications.…”