Photoluminescence from n-type porous silicon layer enhanced by a forward-biased np-junction

Abstract

A new approach for the fabrication of n-type porous silicon layer is proposed. A hole-rich p-layer is arranged underneath the n-layer, and the np-junction is under forward biased condition in the etching process. Therefore sufficient holes can drift straight-upward and pass across the np-junction from p-region to n-region to participate in electrochemical reaction during the etching process with an unfailing supply. Illumination is an optional hole-supplier in this approach, so the problem of illumination-depth limitation can be overcome. Strong visible photoluminescence emissions are demonstrated on the hole-poor n-type porous layer at about 650 nm.

White-light emissions from p-type porous silicon layers by high-temperature thermal annealing

“…However, the visible-light emissions from PS structures usually only appear in the red-light wavelength region by conventional manufacturing methods. The white-light emissions including blue light are still difficult to observe in PS samples to date [3].…”

A high sensitivity double-roughness-structure based on the porous silicon with graphene embedded for the sensing improvement on the non-reactive molecules

“…Our team has successively put forward some novel manufacturing approaches of PS-layers. Among them, the "bottom-hole assisted approach" [5] may produce higher quality PS-films from the np-junction-type Si (denoted as np-PS in the paper) than those build on the conventional p-type Si (denoted as p-PS) or n-type Si (denoted as n-PS). By the approach, the buried p-layer may supply abundant and persistent holes to anticipate the electrochemical reactions on the surface of Si during the anodization.…”

Forming a Photoluminescent Layer on Another Surface in the Dark through Lasering of N-Type Silicon in an Electrolyte

“… 6 , 7 Therefore, according to common sense, it is quite difficult to etch n-type silicon in HF-based electrolytes via a bias process unless holes are generated by strong light irradiation, 8 , 9 the addition of strong oxidants, 10 or the creation of a p–n junction structure. 11 …”

“…6,7 Therefore, according to common sense, it is quite difficult to etch n-type silicon in HF-based electrolytes via a bias process unless holes are generated by strong light irradiation, 8,9 the addition of strong oxidants, 10 or the creation of a p−n junction structure. 11 An alternative method to applying a bias is photoetching processing. 12 This method is applied to n-type silicon by using a Xe light or laser with a wavelength shorter than 600 nm, allowing band gap absorption.…”

“…As generally recognized in academic publications, electrochemical etching with an applied bias is an effective and simple method for fabricating a PS layer and creating a PL layer . In this method, holes are the key to silicon etching in a hydrofluoric acid (HF)-based electrolyte during anodization. , Therefore, according to common sense, it is quite difficult to etch n-type silicon in HF-based electrolytes via a bias process unless holes are generated by strong light irradiation, , the addition of strong oxidants, or the creation of a p–n junction structure …”