Auger quenching-based modulation of electroluminescence from ion-implanted silicon nanocrystals

Abstract

Abstract. We describe high-speed control of light from silicon nanocrystals under electrical excitation. The nanocrystals are fabricated by ion implantation of Si + in the 15-nm-thick gate oxide of a field effect transistor at 6.5 keV. A characteristic readpeaked electroluminescence is obtained either by DC or AC gate excitation. However, AC gate excitation it is found to have a frequency response that is limited by the radiative lifetimes of silicon nanocrystals, which make impossible the direct modulation of light beyond 100 Kb/s rates. As a solution, we demonstrate that combined DC gate excitation along with an AC channel hot electron injection of electrons into the nanocrystals may be used to obtain a 100%-deep modulation at rates of 200 Mb/s and low modulating voltages. This approach, may find applications in biological sensing integrated into CMOS, single-photon emitters, or direct encoding of information into light from Si-nc doped with Erbium systems, which exhibit net optical gain. In this respect, the main advantage compared to conventional electro-optical modulators based on plasma dispersion effects is the low power consumption (10 5 times smaller) and thus the inherent large scale of integration. A detailed electrical characterization is also given. A Si/SiO 2 barrier change from Φ b =3.2 eV to 4.2 eV is found while the injection mechanism is changed from Fowler-Nordheim to Channel Hot Electron, which is a clear signature of nanocrystal charging and subsequent electroluminescence quenching.

Power efficiency estimation of silicon nanocrystals based light emitting devices in alternating current regime

“…It is observed that the EL increases significantly as the frequency increases, it reaches a maximum and then it decreases. In the literature, [1][2][3][4][5] this increase in EL is attributed to an efficiency increase while the decrease, at higher frequencies, is attributed to the Auger suppression of EL due to the finite exciton recombination lifetime.…”

“…Marconi, 1,a͒ A. Anopchenko, 1 G. Pucker, 2 The power efficiency of silicon nanocrystal light-emitting devices is studied in alternating current ͑ac͒ regime. An experimental method based on impedance spectroscopy is proposed.…”

“…In addition, ac driving is also believed to increase the efficiency of these devices. In most of the works in which the AC power efficiency measurements, the value of power efficiency is not quoted [1][2][3][4] or the accuracy of its estimation is unclear. 5 This is mainly due to the difficulty to measure the low currents flowing through the devices and it is complicated by the driving frequency values.…”

Visible electroluminescence on FTO/thin SRO/n-Si structures

“…In this case, it is clearly observed that the charge transport in both directions is increased as thickness is decreased. According to I-V curves, the mechanism of carrier injection through the SRO in devices may involve contributions of direct tunneling and the typical exponential behavior of the Fowler-Nordheim tunneling [27][28][29].…”

Comparative study of the nonlinear optical properties of Si nanocrystals fabricated by e‐beam evaporation, PECVD or LPCVD

“…The nonlinear optical properties of Si-nc have been extensively studied in recent years, in particular to facilitate applications such as light modulation and amplification [3][4][5]. For their fabrication, several approaches have been widely employed, such as laser ablation [6], ion implantation [7], cosputtering [8], evaporation [9,10], plasma enhanced or low pressure chemical vapor deposition (PECVD and LPCVD, respectively) [11][12][13].…”