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

TL;DR

This study reports the synthesis of high-density GeSe triangular nanoplate arrays on Si substrates and investigates their temperature-dependent photoluminescence, revealing a new PL peak related to nanoplate thickness with potential for nanodevice applications.

Contribution

It introduces a simple thermal evaporation method to grow high-density GeSe nanoplate arrays with detailed structural and optical characterization, including novel temperature-dependent PL behavior.

Findings

High-density GeSe TNAs achieved on Si substrates.

Observation of a new PL peak at 1.25 eV at 5 K.

PL peak related to nanoplate thickness.

Abstract

We have grown germanium selenide (GeSe) triangular nanoplate arrays (TNAs) with a high density (3.82E+6 / mm2) on the Si (111) substrate using a simple thermal evaporation method. The thickness and trilateral lengths of a single triangular nanoplate were statistically estimated by atomic force microscopy (AFM) as 44 nm, 365 nm, 458 nm and 605 nm, respectively. Transmission electron microscopy (TEM) images and X-ray diffraction (XRD) patterns show that the TNAs were composed of single crystalline GeSe phase. The Se-related defects in the lattice were also revealed by TEM images and Raman vibration modes. Unlike previously reported GeSe compounds, the GeSe TNAs exhibited temperature-dependent photoluminescence (PL). In addition, not previously reported PL peak (1.25 eV) of the 44 nm thick TNAs at 5 K was in the gaps between those of GeSe monolayers (1.5 nm) and thin films (400 nm), revealing a close relationship between the PL peak and the thickness of GeSe. The high-density structure and temperature-dependent PL of the TNAs on the Si substrate may be useful for temperature controllable semiconductor nanodevices.