Trace explosive detection using photothermal deflection spectroscopy

2008 ◽  
Vol 103 (9) ◽  
pp. 094906 ◽  
Author(s):  
Adam R. Krause ◽  
Charles Van Neste ◽  
Larry Senesac ◽  
Thomas Thundat ◽  
Eric Finot
Keyword(s):  
Explosive Detection ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

scholarly journals Photothermal Deflection Spectroscopy Study of Nanocrystalline Si (nc-Si) Thin Films Deposited on Porous Aluminum with PECVD

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. Ktifa ◽  
M. Ghrib ◽  
F. Saadallah ◽  
H. Ezzaouia ◽  
N. Yacoubi
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Porous Aluminum ◽  
Force Microscopy ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force ◽  
Photothermal Deflection ◽  
Morphology Characterization

We have studied the optical properties of nanocrystalline silicon (nc-Si) film deposited by plasma enhancement chemical vapor deposition (PECVD) on porous aluminum structure using, respectively, the Photothermal Deflection Spectroscopy (PDS) and Photoluminescence (PL). The aim of this work is to investigate the influence of anodisation current on the optical properties of the porous aluminum silicon layers (PASL). The morphology characterization studied by atomic force microscopy (AFM) technique has shown that the grain size of (nc-Si) increases with the anodisation current. However, a band gap shift of the energy gap was observed.

scholarly journals Hydrogen related effects in a-Si:H studied by photothermal deflection spectroscopy

1991 ◽  
pp. 269-272
Author(s):  
J. Serra ◽  
J. Andreu ◽  
G. Sardin ◽  
C. Roch ◽  
J.M. Asensi ◽  
...  
Keyword(s):  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

Photoluminescence in B-doped μc-Si:H

1992 ◽  
Vol 283 ◽  
Author(s):  
S. Q. Gu ◽  
J. M. Viner ◽  
P. C. Taylor ◽  
M. J. Williams ◽  
W. A. Turner ◽  
...  
Keyword(s):  
Broad Band ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Dark Conductivity ◽  
Microcrystalline Silicon ◽  
Band Tail ◽  
Pl Spectra ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Hydrogenated Amorphous

ABSTRACTPhotoluminescence (PL) has been investigated in hydrogenated microcrystalline silicon (μc-Si:H) samples as a function of boron doping for films prepared by remote plasma enhanced chemical vapor deposition. When the dark conductivity a is below about 10-5 S/cm, the PL spectra exhibit a shape which is close to that of the so-called band tail PL in undoped hydrogenated amorphous silicon (a-Si:H) at 77 K. When a increases, the PL intensity decreases at 77 K. For samples with a on the order of 10-3 S/cm, the PL spectra show only a narrow, low energy PL band which peaks around 0.8–0.9 eV. In these samples, the PL at higher energy is essentially not observable. This trend is similar to that which occurs in doped a-Si:H. However, for higher doping levels (σ ∼ 1 S/cm) the PL in μc-Si:H, although very weak, exhibits a broad band which contains intensity at higher energies. The absorption spectra in these samples, as measured by photothermal deflection spectroscopy (PDS), show the same relationships with the corresponding PL spectra as do the PDS spectra in doped a-Si:H.

The Feasibility of Using Photothermal Deflection Spectroscopy to Measure Thermal Contact Resistance in a Film on Substrate System

2001 ◽  
Author(s):  
Jason R. Foley ◽  
C. Thomas Avedisian
Keyword(s):  
Film Thickness ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Bulk Material ◽  
Thermal Contact ◽  
Standard Reference Materials ◽  
Beam Deflection ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Absorbing Layer

Abstract In this paper we extend the theory of photothermal deflection spectroscopy for an isotropic film-on-substrate system to include the thermal contact resistance between the two materials and absorption of energy in the film and substrate. The model is formulated as a three-domain system (gas, film and substrate) with coupling conditions at the various interfaces, including a thermal contact resistance. Closed form expressions are obtained for the temperatures in each domain. The analysis for probe beam deflection is confirmed by comparison to well-known limits of infinite film thickness, zero film thickness, zero contact resistance, and a thin absorbing layer at the surface of the film. The formulations are tested against NIST standard reference materials (SRM) using numerically generated beam deflection data to extract thermal diffusivity of a bulk material, and of two SRMs pressed together to extract thermal contact resistance. The results show the feasibility of using to determine the thermal contact resistance of a layered sample from beam deflection data.

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