Photoluminescence of a Single-Crystal Silicon Quantum Well

1994 ◽  
Vol 358 ◽  
Author(s):  
Peter N. Saeta ◽  
Alan C. Gallagher

ABSTRACTSingle crystal-silicon quantum well layers with SiO2 barriers were grown from silicon-on-insulator substrates. Photoluminescence in the red and near-infrared was observed for average layer thickness < 8 nm, with peak signal for 2-nm thickness. The luminescence spectrum was essentially independent of well width for SiO2 barriers, but the photoluminescence intensity decreased sharply after annealing in Ar. These results suggest the importance of radiation from surface states. In contrast to oxide-passivated silicon nanocrystals and to porous silicon, the room-temperature photoluminescence quantum efficiency is low (10-4-10-5), probably due to variations in layer thickness and to diffusion of photoexcited carriers to fast nonradiative recombination centers.

Author(s):  
N. Lewis ◽  
E. L. Hall ◽  
A. Mogro-Campero ◽  
R. P. Love

The formation of buried oxide structures in single crystal silicon by high-dose oxygen ion implantation has received considerable attention recently for applications in advanced electronic device fabrication. This process is performed in a vacuum, and under the proper implantation conditions results in a silicon-on-insulator (SOI) structure with a top single crystal silicon layer on an amorphous silicon dioxide layer. The top Si layer has the same orientation as the silicon substrate. The quality of the outermost portion of the Si top layer is important in device fabrication since it either can be used directly to build devices, or epitaxial Si may be grown on this layer. Therefore, careful characterization of the results of the ion implantation process is essential.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1118
Author(s):  
Yuan Tian ◽  
Yi Liu ◽  
Yang Wang ◽  
Jia Xu ◽  
Xiaomei Yu

In this paper, a polyimide (PI)/Si/SiO2-based piezoresistive microcantilever biosensor was developed to achieve a trace level detection for aflatoxin B1. To take advantage of both the high piezoresistance coefficient of single-crystal silicon and the small spring constant of PI, the flexible piezoresistive microcantilever was designed using the buried oxide (BOX) layer of a silicon-on-insulator (SOI) wafer as a bottom passivation layer, the topmost single-crystal silicon layer as a piezoresistor layer, and a thin PI film as a top passivation layer. To obtain higher sensitivity and output voltage stability, four identical piezoresistors, two of which were located in the substrate and two integrated in the microcantilevers, were composed of a quarter-bridge configuration wheatstone bridge. The fabricated PI/Si/SiO2 microcantilever showed good mechanical properties with a spring constant of 21.31 nN/μm and a deflection sensitivity of 3.54 × 10−7 nm−1. The microcantilever biosensor also showed a stable voltage output in the Phosphate Buffered Saline (PBS) buffer with a fluctuation less than 1 μV @ 3 V. By functionalizing anti-aflatoxin B1 on the sensing piezoresistive microcantilever with a biotin avidin system (BAS), a linear aflatoxin B1 detection concentration resulting from 1 ng/mL to 100 ng/mL was obtained, and the toxic molecule detection also showed good specificity. The experimental results indicate that the PI/Si/SiO2 flexible piezoresistive microcantilever biosensor has excellent abilities in trace-level and specific detections of aflatoxin B1 and other biomolecules.


2020 ◽  
pp. 100107
Author(s):  
L.G. Michaud ◽  
E. Azrak ◽  
C. Castan ◽  
F. Fournel ◽  
F. Rieutord ◽  
...  

Author(s):  
Wenjun Liu ◽  
Mehdi Asheghi ◽  
K. E. Goodson

Simulations of the temperature field in Silicon-on-Insulator (SOI) and strained-Si transistors can benefit from experimental data and modeling of the thin silicon layer thermal conductivity at high temperatures. This work presents the first experimental data for 20 and 100 nm thick single crystal silicon layers at high temperatures and develops algebraic expressions to account for the reduction in thermal conductivity due to the phonon-boundary scattering for pure and doped silicon layers. The model applies to temperatures range 300–1000 K for silicon layer thicknesses from 10 nm to 1 μm (and even bulk) and agrees well with the experimental data. In addition, the model has an excellent agreement with the predictions of thin film thermal conductivity based on thermal conductivity integral and Boltzmann transport equation, although it is significantly more robust and convenient for integration into device simulators. The experimental data and predictions are required for accurate thermal simulation of the semiconductor devices, nanostructures and in particular the SOI and strained-Si transistors.


2000 ◽  
Author(s):  
John M. Maloney ◽  
Don L. DeVoe ◽  
David S. Schreiber

Abstract Thermal actuators that deflect laterally by resistive heating have been fabricated in single crystal silicon (SCS) by deep reactive ion etching (DRIE). With heights of 50 μm, these high-aspect actuators produce significantly larger forces than similar polysilicon devices. Problems with stiction are also avoided through the use of silicon-on-insulator (SOI) technology. An analytical model is applied to U-beam and V-beam actuator shapes fabricated on SOI wafers. The electrothermal component of the analysis uses an axial conduction model to predict temperature distribution; the thermomechanical component employs elastic beam theory to calculate deflection due to thermal strain. Experimental results are compared to analytical predictions. Deflections of 29 μm for a 1200 μm long, 12 μm wide V-beam actuator were observed, corresponding to a predicted force of 7.6 mN.


1994 ◽  
Vol 358 ◽  
Author(s):  
W. B. Dubbelday ◽  
S. D. Russell ◽  
K. L. Kavanagh

ABSTRACTIn previous work we reported that porous silicon (PS) films formed using a dilute HF:HNO3 chemical etch on polycrystalline, implant damaged single crystal, or amorphous starting material have luminescent characteristics that differ from PS fabricated on single crystal silicon1. Polycrystalline and implant damaged porous silicon exhibits brighter luminescence compared to single crystal silicon etched under identical conditions. No photoluminescence is detected from the porous amorphous silicon. In this work these effects are examined using HF:NaNO2 solutions with freely available NO2. The accelerated etching effects from work damage are reduced, and the PS from polycrystalline and implant damaged silicon luminesce with the same intensity as the PS from single crystal silicon. Again, etched amorphous silicon does not luminesce. TEM and EDX porosity measurements are used to determine the differences in structure and etching characteristics between the luminescent and non-luminescent materials.


1984 ◽  
Vol 33 ◽  
Author(s):  
P. Zorabedian ◽  
T. I. Kamins

ABSTRACTTwo scanning methods for laterally-seeded recrystallization of striped silicon-on-insulator/seed structures with an elliptical laser beam are discussed. One method requires repeated remelting of the silicon film and is controlled by the temperature of the substrate, which is locally heated by the beam. This method results in very few defects and single-crystal silicon-on-insulator stripes up to 50 μm wide. The second method involves little remelting and is primarily controlled by the lateral offset of the beam with respect to the stripes. Single-crystal silicon-on-insulator stripes up to 40 μm wide have been obtained, with defects consisting primarily of stacking faults and twins, as well as some grain boundaries. These defects show little effect on MOS transistor leakage current.


2008 ◽  
Vol 1080 ◽  
Author(s):  
Ataur Sarkar ◽  
M. Saif Islam ◽  
Sungsoo Yi ◽  
A. Alec Talin

ABSTRACTRoom temperature photoelectrical characterization with 325-nm ultraviolet and 633-nm visible laser excitations is performed on lateral p-type InP nanowires bridged between vertically oriented heavily p-doped single crystal silicon electrodes. Experimental results under 5 V bias demonstrate persistent photoconductivity through a slow decay of excess photocurrent with relaxation times ∼110 s and ∼50 s for the UV and visible laser illuminations, respectively. Persistent photocurrent originates from the long recombination time due to carrier trapping in vacancies, defect centers, and surface states in the InP nanowires. The study opens a new understanding of trap physics of nanowire heterostructures, a critical investigation for applications of these materials in photonic devices.


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