• Title/Summary/Keyword: porous silicon

Search Result 340, Processing Time 0.021 seconds

Photoluminescence of Porous Silicon Carbide in Solvents

  • Lee, Ki-Hwan;Lee, Tae-Ho;Yoon, Seok-Won;Lee, Seung-Koo;Jeon, Hae-Kwon;Choi, Chang-Shik
    • Journal of Photoscience
    • /
    • v.12 no.3
    • /
    • pp.171-174
    • /
    • 2005
  • The relationship between porous surfaces and photoluminescence (PL) behavior of porous silicon carbide (PSC) in various solvents has been studied. The porous surfaces of p-type silicon carbide can be fabricated by electrochemical anodization from the 6H, 15R, 4H-${\alpha}$-SiC substrates in dark-current mode (DCM) condition. We have been investigated the dependence of the PL spectra of PSC under the medium having the different dielectric constants. It has been found that PL depends sensitively on the environment surrounding the surface. The extent of chemically stability on the surface of PSC due to the various solvents was confirmed by reflectance Fourier transform infrared (FTIR) spectroscopy. Detailed IR experiments on the PSC samples were carried out before and after various solvents immersion. These results will be offered important information on the origin of PL in porous structure.

  • PDF

Optimization of Electrochemical Etching Parameters in Porous Silicon Layer Transfer Process for Thin Film Solar Cell (초박형 태양전지 제작에 Porous Silicon Layer Transfer기술 적용을 위한 전기화학적 실리콘 에칭 조건 최적화에 관한 연구)

  • Lee, Ju-Young;Koo, Yeon-Soo;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.18 no.1
    • /
    • pp.23-27
    • /
    • 2011
  • Fabrication of porous silicon(PS) double layer by electrochemical etching is the first step in process of ultrathin solar cell using PS layer transfer process. The porosity of the porous silicon layer can be controlled by regulating the formation parameters such as current density and HF concentration. PS layer is fabricated by electrochemical etching in a chemical mixture of HF and ethanol. For electrochemical etching, highly boron doped (100) oriented monocrystalline Si substrates was used. Ths resistivity of silicon is $0.01-0.02\;{\Omega}{\cdot}cm$. The solution composition for electrochemical etching was HF (40%) : $C_2H_5OH$(99 %) : $H_2O$ = 1 : 1 : 2 (by volume). In order to fabricate porous silicon double layer, current density was switched. By switching current density from low to high level, a high-porosity layer was fabricated beneath a low-porosity layer. Etching time affects only the depth of porous silicon layer.

Fabrication via Ultrasonication and Study of Silicon Nanoparticles

  • Kim, Jin Soo;Sohn, Honglae
    • Journal of Integrative Natural Science
    • /
    • v.8 no.3
    • /
    • pp.147-152
    • /
    • 2015
  • Photoluminescent porous silicon (PSi) were prepared by an electrochemical etch of n-type silicon under the illumination with a 300 W tungsten filament bulb for the duration of etch. The red photoluminescence emitting at 620 nm with an excitation wavelength of 450 nm is due to the quantum confinement of silicon nanocrystal in porous silicon. As-prepared PSi was sonicated, fractured, and centrifuged in toluene to obtain photoluminescence silicon quantum dots. BET and BHJ methods were employed to study the specific surface area of as-prepared PSi. Optical characterization of red photoluminescent silicon nanocrystal was investigated by UV-vis and fluorescence spectrometer. Also SEM and TEM images of porous silicon and nanoparticles were investigated.

Fabrication and Characteristics of MMIC Substrate using Oxidation of Porous Silicon (다공질 실리콘 산화법을 이용한 MMIC 기판의 제조 및 그 특성)

  • Kwon, O.J.;Kim, K.J.;Lee, J.S.;Lee, J.H.;Choi, H.C.;Lee, J.H.;Kim, K.W.
    • Journal of Sensor Science and Technology
    • /
    • v.8 no.2
    • /
    • pp.202-209
    • /
    • 1999
  • Microstrip line was fabricated on the oxidized porous silicon layer which has nearly electrically and chemically identical properties with thermally oxidized silicon layer. Thick oxidized porous silicon layer of few tenth of micrometers was prepared by thermal oxidation of porous silicon layer on silicon substrate. Multi-step thermal oxidation process was used to obtain high Quality and thick oxidized silicon layer and to release thermal stress. Microstrip line was fabricated on the oxidized porous silicon layer. Its microwave characteristics were measured and the availability for MMIC substrate was investigated.

  • PDF

Development of Porous Silicon Electro-osmotic Pumps for High Flow Rate Per Current Flow Delivery of Organic Solvents (단위전류당 고유량 유기용매 이송을 위한 다공성 실리콘막 전기침투 펌프의 개발)

  • Kwon, Kil-Sung;Kim, Dae-Joong
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.34 no.2
    • /
    • pp.105-111
    • /
    • 2010
  • Two types of electro-osmotic pumps were prepared: with anodized and DRIE porous silicon. The pump performance was characterized for both types in terms of flow rate and flow rate per current using organic solvents. Both types of electro-osmotic pumps showed a better performance compared to porous glass electro-osmotic pumps. The DRIE porous silicon electro-osmotic pump especially demonstrated an excellent flow rate and flow rate per current performance. The DRIE porous silicon electro-osmotic pump is expected to help in the development of electro-osmotic pumps and micropumps in general due to the recently widespread availability of DRIE processes.

Chemical and Physical Properties of Porous Silicon

  • Lee, Bo-Yeon;Hwang, Minwoo;Cho, Hyun;Kim, Hee-Chol;Jang, Seunghyun
    • Journal of Integrative Natural Science
    • /
    • v.4 no.3
    • /
    • pp.187-191
    • /
    • 2011
  • The differences of properties for both single-layered and multi-layered porous silicon were investigated. Multistructured porous silicons such as DBR or rugate porous silicon exhibit strong reflection resonances providing the reflection of a specific wavelength in the optical reflectivity spectrum. DBR PSi displays a square varying porosity gradient in the direction perpendicular to the plane of the filter but a sinusoidally varying porosity gradient was obtained for rugate PSi.

Effect of Si/$Si_3N_4$ Ration on the Micro structure and Properties of Porous Silicon Nitride Prepared by SHS Method (규소/질화규소 비가 자전연소합성공정을 이용한 다공질 질화규소 세라믹스의 미세구조와 특성에 미치는 영향)

  • Kim, Dong-Baek;Park, Dong-Su;Han, Byeong-Dong;Jeong, Yeon-Gil
    • 연구논문집
    • /
    • s.34
    • /
    • pp.131-138
    • /
    • 2004
  • Porous silicon nitride ceramics were prepared by Self-propagating High Temperature Synthesis from silicon powder, silicon nitride powder and the pore-forming precursor. The microstructure, porosity and the flexural strength of the porous silicon nitride ceramics were varied according to the Si/$Si_3N_4$ ratio, size and amount of the pore-forming precursors. Some samples exhibited as high flexural strength as $162\pm24$ MPa. The high strength is considered to result from the fine pore size and the strong bonding among the silicon nitrid particles.

  • PDF

A Porous Silicon-Based Capacitive Humidity Sensor (다공질 실리콘 산화막을 이용한 용량형 습도 센서)

  • Min, Nam-Ki;Chin, Min-Suk;Ahn, Kwang-Ho
    • Proceedings of the KIEE Conference
    • /
    • 1995.07c
    • /
    • pp.1209-1212
    • /
    • 1995
  • This paper presents a capacitive humidity sensor using porous silicon layers formed tom the anodization of p-type silicon in HF solution. The upper electrodes consist of many aluminum strips over porous silicon, between which the porous silicon is etched away. The sensor showed a good sensitivity(20pF/%RH) and lineaity in the range of 40%RH$\sim$80%RH, a hysteresis of ${\pm}2%$ RH, and a slow transient response. These preliminary resluts show that futher improvement can still be expected.

  • PDF

Structural and Optical Properties of Porous Silicon Prepared by Electrochemical Etching

  • Lee, Jeong-Seok;Cho, Nam-Hee
    • Journal of the Korean Ceramic Society
    • /
    • v.39 no.2
    • /
    • pp.109-112
    • /
    • 2002
  • The structural and optical features of Porous Silicon(PS) were investigated; the porous silicon was prepared by electrochemical etching of silicon wafers in HF solution. The morphologies and Photoluminescece(PL) features of the PS were investigated in terms of etching time, current density and aging conditions. The average pore diameter and pore depth were determined by current density and etching time, respectively. As-prepared PS exhibited the maximum PL peak at the wavelength of ∼ 450 nm. The degree of deviation from as-prepared PS during aging treatment seemed to depend on the microstructure as well as morphology of the PS. It is found that etching current density played an important role on the microstructural features of the PS.

Deposition and Photoluminescence Characteristics of Silicon Carbide Thin Films on Porous Silicon (다공성실리콘 위의 탄화규소 박막의 증착 및 발광특성)

  • 전희준;최두진;장수경;심은덕
    • Journal of the Korean Ceramic Society
    • /
    • v.35 no.5
    • /
    • pp.486-492
    • /
    • 1998
  • Silicon carbide (SiC) thin films were deposited on the porous silicon substrates by chemical vapour de-position(CVD) using MTS as a source material. The deposited films were ${\beta}$-SiC with poor crystallity con-firmed by XRD measurement. It was considered that the films showed the mixed characteistics of cry-stalline and amorphous SiC where amorphous SiC where amorphous SiC played a role of buffer layer in interface between as-dep films and Si substrate. The buffer layer reduced lattice mismatch to some extent the generally occurs when SiC films are deposited on Si. The low temperature (10K) PL (phtoluminescence) studies showed two broad bands with peaks at 600 and 720 for the films deposited at 1100$^{\circ}C$ The maximum PL peak of the crystalline SiC was observed at 600 nm and the amrophous SiC of 720 nm was also confirmed. PL peak due the amorphous SiC was smaller than that of the crystalline SiC, PL of porous Si might be disapperared due to densification during heat treatment.

  • PDF