Demonstration of photoluminescence in nonanodized silicon

Abstract

The formation of photoluminescent porous Si in an &chant solution made from the HF-HNOs-CH,COOH system is reported. The porous Si is characterized on the basis of its photoluminescence (PL) spectra and the degradation of the PL during exposure to laser irradiation. The surface topography as characterized by atomic force microscopy (AFM) reveals features on the order of 400-600 A. The effect of annealing the porous Si in vacuum on the PL intensity is described and correlated to the breakdown of Si-H bonds on the porous Si surface.

Properties of light-emitting porous silicon photoetched in aqueous HF∕FeCl3 solution

“…3͑a͒ and 3͑c͔͒ exhibit a broad emission peaking at ϳ2.0− 2.1 eV, which is typically observed in stain etched PSi samples in HF/ HNO 3 -based solutions. 3,[9][10][11][12][13][14] The stain etched sample in the 47 wt % solution ͓Fig. 3͑d͔͒ also exhibits a broad peak at ϳ2 eV.…”

“…The use of a Xe lamp enables a formation of large, homogeneous PSi layers. The addition of oxidant FeCl 3 in HF results in a stable formation of PSi layers in very short time. Properties of the photoetched PSi layers are characterized using photoluminescence ͑PL͒, atomic force microscopy ͑AFM͒, and Fourier-transform infrared spectroscopy ͑FTIR͒.…”

“…1,2 Such luminescent PSi layers are commonly formed by anodic etching on p-type silicon substrates. The first report of a luminescent porous layer obtained without electrochemical anodization came from Sarathy et al 3 who used a stain etching in a HF/ HNO 3 solution. Noguchi and Suemune 4 demonstrated the formation of a luminescent PSi spot by photoetching in a HF solution under He-Ne laser illumination for ϳ60 min.…”

Spectroscopic investigation of light-emitting porous silicon photoetched in aqueous HF∕I2 solution

“…The PSi layers can also be formed by simply immersing a Si wafer in a HF-based solution without ͑stain etching͒ or with light illumination ͑photoetching͒. The first report of a light-emitting PSi layer obtained by stain etching came from Sarathy et al 4 who used an aqueous HF/ HNO 3 solution. Some authors also demonstrated the formation of a luminescent PSi by photoetching in HF-based solutions under HeϪNe laser illumination.…”

“…[10][11][12] The stain and photoetched PSi films have been suggested as being similar in nature to the anodically etched PSi films. [4][5][6][7][8][9][10][11][12] The purpose of this article is to make clear the optical properties of PSi photoetched in aqueous HF/ I 2 solution. To study the nanostructure properties of PSi, we perform spectroellipsomety ͑SE͒, electroreflectance ͑ER͒, photovoltage ͑PV͒, photoconductivity ͑PC͒, and Fourier transform infrared ͑FTIR͒ spectroscopy measurements.…”