Solution-Synthesized High-Mobility Tellurium Nanoflakes for Short-Wave Infrared Photodetectors

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Matin Amani
  • George Zhang
  • Chunsong Zhao
  • James Bullock
  • Xiaohui Song
  • Hyungjin Kim
  • Vivek Raj Shrestha
  • Yang Gao
  • Kenneth B. Crozier
  • Mary Scott
  • Ali Javey

Detail(s)

Original languageEnglish
Pages (from-to)7253-7263
Journal / PublicationACS Nano
Volume12
Issue number7
Online published18 Jun 2018
Publication statusPublished - 24 Jul 2018
Externally publishedYes

Abstract

Two-dimensional (2D) materials, particularly black phosphorus (bP), have demonstrated themselves to be excellent candidates for high-performance infrared photodetectors and transistors. However, high-quality bP can be obtained only via mechanical exfoliation from high-temperature- and high-pressure-grown bulk crystals and degrades rapidly when exposed to ambient conditions. Here, we report solution-synthesized and air-stable quasi-2D tellurium (Te) nanoflakes for short-wave infrared (SWIR) photodetectors. We perform comprehensive optical characterization via polarization-resolved transmission and reflection measurements and report the absorbance and complex refractive index of Te crystals. It is found that this material is an indirect semiconductor with a band gap of 0.31 eV. From temperature-dependent electrical measurements, we confirm this band-gap value and find that 12 nm thick Te nanoflakes show high hole mobilities of 450 and 1430 cm2 V-1 s-1 at 300 and 77 K, respectively. Finally, we demonstrate that despite its indirect band gap, Te can be utilized for high-performance SWIR photodetectors by employing optical cavity substrates consisting of Au/Al2O3 to dramatically increase the absorption in the semiconductor. By changing the thickness of the Al2O3 cavity, the peak responsivity of Te photoconductors can be tuned from 1.4 μm (13 A/W) to 2.4 μm (8 A/W) with a cutoff wavelength of 3.4 μm, fully capturing the SWIR band. An optimized room-temperature specific detectivity (D) of 2 × 109 cm Hz1/2 W-1 is obtained at a wavelength of 1.7 μm.

Research Area(s)

  • 2D materials, high-mobility, photodetectors, short-wave infrared, solution-synthesized, tellurium

Citation Format(s)

Solution-Synthesized High-Mobility Tellurium Nanoflakes for Short-Wave Infrared Photodetectors. / Amani, Matin; Tan, Chaoliang; Zhang, George et al.

In: ACS Nano, Vol. 12, No. 7, 24.07.2018, p. 7253-7263.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review