Anisotropic Photoresponse of the Ultrathin GeSe Nanoplates Grown by Rapid Physical Vapor Deposition

Abstract

Anisotropic materials, especially two-dimensional (2D) layered materials formed by van der Waals force (vdW) with low-symmetry, have become a scientific hot-spot because their electrical, optical, and thermoelectric properties are highly polarization dependent. The 2D GeSe, a typical anisotropic-layered orthorhombic structure and narrow bandgap (1.1−1.2 eV) semiconductor, potentially meets these demands. In this report, the ultrathin elongated hexagonal GeSe nanoplates were successfully synthesized by the rapid physical vapor deposition method developed here. The ultrathin elongated hexagonal GeSe nanoplates have a zigzag edge in the long edge and an armchair edge in the short edge. In addition, the typical Raman mode exhibited 90°p eriodic vibration, having its maximum intensity between the zigzag direction or the zigzag and armchair direction, indicating an anisotropic electron−phonon interaction. Furthermore, the field effect transistor devices based on the elongated hexagonal GeSe nanoplates were constructed and exhibited the p-type semiconducting behavior with a high photoresponse characteriscs. Finally, the polarized sensitive photocurrent was identified, further revealing the intrinsically anisotropy of the GeSe nanoplate. The results illustrated here may give a useful guidance to synthesize the 2D-layered anisotropic nanomaterials and further advance the development of the polarized photodetector.

In-plane anisotropic electronics based on low-symmetry 2D materials: progress and prospects

“…also possess puckered orthorhombic (distorted NaCl-type) crystal structure and exhibit high Grüneisen parameters, which give rise to ultralow thermal conductivities and exceptionally high thermoelectric gures of merit. 12,75 In addition, their lowsymmetry crystal structures can lead to highly anisotropic behaviors manifested in, such as, the in-plane anisotropic carrier's mobility, [76][77][78] photoresponse, 42,[79][80][81][82] and Raman intensity. 78,83,84 Conventionally, the zigzag accordion-like projection is dened as x-axis and y-axis denoting the armchair direction.…”

Recent Advances in 2D Metal Monochalcogenides

“…Such anisotropy in along armchair and zigzag direction pave a new root to employ GeSe for novel optoelectronics applications. In addition, Liu et al [193] have also investigated similar anisotropic electronic properties in GeSe devices. Figure 14h presents the schematic diagram of the angle-resolved transport setup they used for electrical anisotropy measurements.…”

Synthesis and photoluminescence of high density GeSe triangular nanoplate arrays on Si substrates

“…Graphene is one of the most widely studied two-dimensional (2D) materials due to its fascinating mechanical, electronic and optical properties. [1][2][3][4][5][6] Because of the absence of bandgap in graphene, a great amount of effort has been put on finding alternative 2D semiconductors. [7][8][9][10] Recently, IV-VI composite semiconductors (such as GeS, GeSe, SnS and SnSe) have attracted extensive interests because of their natural layered crystalline structure and excellent semiconductor properties.…”

“…[18][19][20][21] Among IV-VI compound semiconductors, GeSe possesses a narrow band gap overlapping well with the solar spectrum, high carrier mobility, low toxicity and air stability, showing great potentials in fabrication of electronic and optoelectronic devices. 18,[21][22][23][24][25] Different GeSe structures including nanoparticles, 26 nanosheets (hexagonal, comb and irregular structures) 3,12,14,18 and thin films 19,25 were fabricated by various methods such as chemical vapor deposition and mechanical exfoliation.…”