Resonant Zener tunnelling via zero-dimensional states in a narrow gap diode.

D M Di Paola,A Patanè,L Eaves,O Makarovsky,M Kesaria,N Mori,A Velichko,A Krier

doi:10.1038/srep32039

D M Di Paola, A Patanè + Show 6 more

Open Access

https://doi.org/10.1038/srep32039

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Abstract

Interband tunnelling of carriers through a forbidden energy gap, known as Zener tunnelling, is a phenomenon of fundamental and technological interest. Its experimental observation in the Esaki p-n semiconductor diode has led to the first demonstration and exploitation of quantum tunnelling in a condensed matter system. Here we demonstrate a new type of Zener tunnelling that involves the resonant transmission of electrons through zero-dimensional (0D) states. In our devices, a narrow quantum well of the mid-infrared (MIR) alloy In(AsN) is placed in the intrinsic (i) layer of a p-i-n diode. The incorporation of nitrogen in the quantum well creates 0D states that are localized on nanometer lengthscales. These levels provide intermediate states that act as “stepping stones” for electrons tunnelling across the diode and give rise to a negative differential resistance (NDR) that is weakly dependent on temperature. These electron transport properties have potential for the development of nanometre-scale non-linear components for electronics and MIR photonics.

Highlights

Interband tunnelling of carriers through a forbidden energy gap, known as Zener tunnelling, is a phenomenon of fundamental and technological interest
The N-induced narrowing of the band gap arises from the hybridization of the extended conduction band (CB) states of InAs with the N-energy levels located above the CB edge[10,11,12]; a more complex picture can arise from crystalline defects, such as N-clusters[13] and/or point defects[14,15], leading to a band structure with admixed localized and delocalized states
We demonstrate that the localized levels induced in the band gap by the N-incorporation provide intermediate states as “stepping stones” for tunnelling of electrons across the p-n junction of a resonant tunnelling diode (RTD), leading to a negative differential resistance (NDR) that is only weakly affected by temperature

Summary

Introduction

Interband tunnelling of carriers through a forbidden energy gap, known as Zener tunnelling, is a phenomenon of fundamental and technological interest. We demonstrate that the localized levels induced in the band gap by the N-incorporation provide intermediate states as “stepping stones” for tunnelling of electrons across the p-n junction of a resonant tunnelling diode (RTD), leading to a negative differential resistance (NDR) that is only weakly affected by temperature. We probe these localized states by magneto-tunnelling spectroscopy (MTS) and demonstrate that they are strongly confined at small length scales, λ0 ~ 1.5 nm, with binding energies much larger than for shallow donors in InAs. The N-induced localized states in InAs provide a novel means of tailoring diode characteristics for electronic and MIR photonic applications

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