On the origin of photoluminescence in spark-eroded (porous) silicon

Hummel, Rolf E.; Morrone, A.; Ludwig, Matthias; Chang, Sung‐Sik

doi:10.1063/1.110792

Cited by 59 publications

(29 citation statements)

References 29 publications

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“…The result [20] which suggests that a high percentage of this material is, indeed, present in the composition of the n-PS columns [4,21]. The results of this best fit is shown in Fig.…”

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confidence: 70%

Photothermal Characterization of Electrochemical Etching Processed n-Type Porous Silicon

et al. 1997

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The room temperature thermal diffusivity evolution of electrochemically formed porous silicon as a function of the etching time is investigated. The measurements were carried out using the open-cell photoacoustic technique. The experimental data were analyzed using a composite two-layer model. The results obtained strongly support the existing studies, indicating the presence of a high percentage of SiO 2 in the composition of porous silicon material. [S0031-9007(97) PACS numbers: 44.30. + v, 61.43.Gt, 81.05.Cy, 81.05.Rm Since the discovery of its room-temperature visible luminescence [1][2][3][4][5], porous silicon (PS) has become a subject of considerable interest, especially for its promising use as an optoelectronic device [6,7]. There are several methods [8][9][10][11] for fabricating PS from crystalline silicon wafers. The electrochemical etching [1,8] is, however, the most extensively used so far. The morphology of the resulting porous layer is strongly dependent upon the fabrication controlling parameters such as electrolyte composition, current density, etching time, etc., as well as on the type of substrate used.In general, an electrochemically formed n-type PS layer consists essentially of a double-layer system on top of the silicon substrate [1,12]. The outermost thin layer, known as the microporous layer, is typically 10-15 mm thick and is responsible for the observed photoluminescence. Except for very small etching times, the inner layer adjacent to the crystalline substrate, designated as the macroporous layer, consists of a parallel array of airembedded free-standing n-PS columns.Despite the large body of literature that already exists on PS [13,14], so far there has been no reported detailed investigation of the thermophysical properties of this important system. In this Letter we apply the modern photothermal techniques to the evaluation of the thermal properties of electrochemically formed n-PS.The samples used in our experiments were prepared by electrochemical etching on (100) oriented, nondegenerated, n-type ͑2.1 3 10 18 cm 23 ͒ crystalline silicon. The samples had a thickness of roughly 300 mm and an electrical resistivity of 1-5 V cm. The electrochemical etching was carried out following the procedure outlined in Ref. [12]. The crystalline samples, with an appropriate Pt network electrode attached to them, were immersed in a 150 ml Becker filled with HF. A current density of 40 mA͞cm 2 was then applied to the samples using a HP-model 6206B dc power supply operating between 5-10 V. During the etching period the samples were always kept under the irradiation of a 250 W infrared lamp positioned roughly 20 cm away from the etching bath. By controlling the etching time, ranging from 10 to 83 min, we could fabricate samples with different macroporous thicknesses.In Fig. 1 we show the side view optical micrograph of a typical n-PS sample, produced with 60 min etching time. The three distinct regions mentioned above, namely, the microporous and macroporous layers on top of the crystalline sub...

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“…The result [20] which suggests that a high percentage of this material is, indeed, present in the composition of the n-PS columns [4,21]. The results of this best fit is shown in Fig.…”

mentioning

confidence: 70%

Photothermal Characterization of Electrochemical Etching Processed n-Type Porous Silicon

et al. 1997

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“…5 is interpreted as crystallite-size related, the estimated average particle diameter is 6 nm [18]. For this size estimation, a spherical shape is assumed, as revealed by the TEM analysis of sp-Si [15]. This size seemed too large to account for quantum-size related luminescence in the near UV/violet and green luminescence.…”

Section: Resultsmentioning

confidence: 99%

“…(Note that the probing depth of X-rays reaches considerably deeper than the spark affected area.) It is quite interesting that spark processing of Si also yields some polycrystalline Si in or on the formerly single crystalline Si [15]. Fig.…”

Section: Resultsmentioning

confidence: 99%

Luminescence properties of spark-processed SiC

Chang

Sakai

2004

Materials Letters

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“…Optical breakdown threshold intensities for Si 3 H 8 The minimum power density required to form a plasma is called the breakdown threshold; different types of laser, sample, and environmental conditions will have different breakdown thresholds. Breakdown thresholds of solids and liquids are usually much lower than those for gases.…”

Section: Resultsmentioning

confidence: 99%

“…These processing technologies generally imply deposition of a film on a substrate as, for example, in experiments with magnetron sputtering, 3 plasma deposition, 4 laser ablation, [5][6][7] and electric spark processing of a silicon wafer. 8 LIB of silane ͑SiH 4 ͒ has been largely used in laser-induced chemical vapor deposition ͑CVD͒ and plasma-enhanced CVD for obtaining amorphous and hydrogenated silicon films. [9][10][11][12][13][14][15] Besides, higher silanes ͑disilane and trisilane͒, more effective in absorbing IR radiation, have been described as very suitable to act as precursors to a-Si: H films and from plasma decomposition induced by glow discharge.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced breakdown spectroscopy of trisilane using infrared CO2 laser pulses

Camacho

Poyato

Díaz

et al. 2007

Journal of Applied Physics

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Synthesis and photoluminescence of fluorinated graphene quantum dots Appl. Phys. Lett. 102, 013111 (2013) The luminescence characteristics of CsI(Na) crystal under α and X/γ excitation J. Appl. Phys. 113, 023101 (2013) Structural and optoelectronic properties of Eu2+-doped nanoscale barium titanates of pseudo-cubic form J. Appl. Phys. 112, 124321 (2012) Quantum yield of luminescence of Ag nanoclusters dispersed within transparent bulk glass vs. glass composition and temperature Appl. Phys. Lett. 101, 251106 (2012) Additional information on J. Appl. Phys. The plasma produced in trisilane ͑Si 3 H 8 ͒ at room temperature and pressures ranging from 50 to 10 3 Pa by laser-induced breakdown ͑LIB͒ has been investigated. The ultraviolet-visible-near infrared emission generated by high-power IR CO 2 laser pulses in Si 3 H 8 has been studied by means of optical emission spectroscopy. Optical breakdown threshold intensities in trisilane at 10.591 m for laser pulse lengths of 100 ns have been measured as a function of gas pressure. The strong emission observed in the plasma region is mainly due to electronic relaxation of excited atomic H and Si and ionic fragments Si + , Si 2+ , and Si 3+ . An excitation temperature T exc = 5600± 300 K was calculated by means of H atomic lines assuming local thermodynamic equilibrium. The physical processes leading to LIB of trisilane in the power density range 0.28 GW cm −2 Ͻ J Ͻ 3.99 GW cm −2 have been analyzed. From our experimental observations we can propose that, although the first electrons must appear via multiphoton ionization, electron cascade is the main mechanism responsible for the breakdown in trisilane.

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On the origin of photoluminescence in spark-eroded (porous) silicon

Cited by 59 publications

References 29 publications

Photothermal Characterization of Electrochemical Etching Processed n-Type Porous Silicon

Photothermal Characterization of Electrochemical Etching Processed n-Type Porous Silicon

Luminescence properties of spark-processed SiC

Laser-induced breakdown spectroscopy of trisilane using infrared CO2 laser pulses

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