Enhanced photoluminescence emission from two-dimensional silicon photonic crystal nanocavities

N Hauke,M Kaniber,K Müller,J J Finley,G Abstreiter,A Laucht,D Bougeard,Y Arakawa,T Zabel

doi:10.1088/1367-2630/12/5/053005

Abstract

We present a temperature-dependent photoluminescence study of silicon optical nanocavities formed by introducing point defects into two-dimensional photonic crystals. In addition to the prominent TO-phonon-assisted transition from crystalline silicon at ∼1.10 eV, we observe a broad defect band luminescence from ∼1.05 to ∼1.09 eV. Spatially resolved spectroscopy demonstrates that this defect band is present only in the region where air holes have been etched during the fabrication process. Detectable emission from the cavity mode persists up to room temperature; in strong contrast, the background emission vanishes for T⩾150 K. An Arrhenius-type analysis of the temperature dependence of the luminescence signal recorded either in resonance with the cavity mode or weakly detuned suggests that the higher temperature stability may arise from an enhanced internal quantum efficiency due to the Purcell effect.

Highlights

We present a temperature-dependent photoluminescence study of silicon optical nanocavities formed by introducing point defects into twodimensional photonic crystals
The high Q-factors that are attainable using photonic crystals (PhCs) nanocavities [10]–[12] together with their small mode volumes may lead to an enhancement of the internal quantum efficiency of the active material due to an increase of the radiative emission rate via the Purcell effect [13]
We present a detailed investigation of the spectrum and temperature stability of the PL emission from crystalline silicon PhC nanocavities

Summary

Introduction

We present a temperature-dependent photoluminescence study of silicon optical nanocavities formed by introducing point defects into twodimensional photonic crystals. The high Q-factors that are attainable using PhC nanocavities [10]–[12] together with their small mode volumes may lead to an enhancement of the internal quantum efficiency of the active material due to an increase of the radiative emission rate via the Purcell effect [13]. Analysis of our results indicates that mainly the phonon satellites of the interband silicon emission and but more weakly, surface defect states are responsible for the luminescence of PhC cavity modes.

Results

Conclusion