Silicon-based electrically driven microcavity LED

Abstract

Introduction: The realisation of Si-based, electrically driven light emitters is a key requirement for the implementation of low-cost Si-based optoelectronics [1]. Realising Si-based light sources in a process technology compatible with mainstream microelectronics technology is one of the big challenges of semiconductor technology. Because of its indirect bandgap Si has a low radiative recombination rate, leading to efficiencies of the bandgap electroluminescence (EL) in the range of 10 � 6 [2, 3]. Recently, different approaches have led to an increase of the power efficiency of the bandgap EL by more than three orders of magnitude up to values of 0.1‐1% [4‐6] .T hese approaches are based on pn-diodes, where either the non-radiative lifetime is increased by using high-purity floatzone Si, combined with surface texturing to improve the outcoupling efficiency [5] ,o r where specific defects introduced by ion implantation enhance the radiative recombination rate through carrier confinement effects [4, 6]. However, the spectral width and temporal response of these devices still constrains their practical application. One possible route for a further enhancement of the efficiency of these devices is a photonic confinement of the emitting layer. III‐V semiconductor based LEDs gained significantly in performance by incorporation into microcavities (MCs) [7]. Planar MCs enhance the brightness, efficiency and directionality of the emission from a high-index material and lead to more than an order of magnitude increase in the spectral power