N.H. Vinayakprasanna; K.C. Praveen; N. Pushpa; Ambuj Tripathi; John D Cressler; A.P. Gnana Prakash
Abstract
The total dose effects of 80 MeV carbon ions and 60 Co gamma radiation in the dose range from 1 Mrad to 100 Mrad on advanced 200 GHz Silicon-Germanium heterojunction bipolar transistors (SiGe HBTs) are investigated. The stopping and range of ions in matter (SRIM) simulation study was conducted to understand ...
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The total dose effects of 80 MeV carbon ions and 60 Co gamma radiation in the dose range from 1 Mrad to 100 Mrad on advanced 200 GHz Silicon-Germanium heterojunction bipolar transistors (SiGe HBTs) are investigated. The stopping and range of ions in matter (SRIM) simulation study was conducted to understand the energy loss of 80 MeV carbon ions in SiGe HBT structure. Pre- and post-radiation DC figure of merits such as Gummel characteristics, excess base current, ideality factor, DC current gain, damage constant, neutral base recombination, avalanche multiplication of carriers and output characteristics were used to quantify the radiation tolerance of the devices. The excess base current, current gain and damage constant for 80 MeV carbon irradiated SiGe HBTs show more degradation when compared to 60 Co gamma irradiation. The ideality factor for 80 MeV carbon ions irradiated SiGe HBTs is also more when compared to 60 Co gamma irradiated SiGe HBTs. The SiGe HBTs shows minimal degradation in current gain at collector current levels (~ 1 mA) where the circuits are biased even after 100 Mrad of total dose. Therefore SiGe HBTs are became the reliable candidate for deep space exploration programs and high energy physics experiments (HEP) like large hadron colliders (LHCs).
Sunita Rattan; Prachi Singhal; Devesh Kumar Avasthi; Ambuj Tripathi
Abstract
Ion implantation is a surface treatment process in which the surface of a sample is bombarded with a beam of energetic dopant ions to implant ions into the matrix of the substrate. In the present work, nanocomposites of poly(3,4-ethylenedioxy thiophene) /poly(4-styrene sulphonate) (PEDOT: PSS) and nanographite ...
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Ion implantation is a surface treatment process in which the surface of a sample is bombarded with a beam of energetic dopant ions to implant ions into the matrix of the substrate. In the present work, nanocomposites of poly(3,4-ethylenedioxy thiophene) /poly(4-styrene sulphonate) (PEDOT: PSS) and nanographite are prepared and subjected to swift heavy ion implantation using the same ion as that of the filler in the nanocomposites. PEDOT: PSS/ nanographite nanocomposites have been synthesized by solution blending method. The prepared PEDOT: PSS/ nanographite nanocomposite films were irradiated with carbon ions (C ion beam, 50 MeV) in fluence range of 3 × 10 10 to 3 × 10 12 ions/cm 2 . The nanocomposite films were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) before and after C ion implantation and were evaluated for their electrical and sensor properties. SEM and XRD studies clearly depict the homogeneous dispersion of nanograhite in polymer matrix along with densification of the polymer nanocomposite. The implanted nanocomposites exhibit better electrical and sensor properties for the detection of nitroaromatics.
R.S. Chauhan; Vijay Kumar; Anshul Jain; Deepti Pratap; D.C. Agarwal; R.J. Chaudhary; Ambuj Tripathi
Abstract
Nanocrystalline tin oxide (SnO2) thin films were fabricated using pulsed laser deposition (PLD) technique. The as-deposited films were irradiated at liquid nitrogen (LN2) temperature using 100 MeV Ag ions at different fluences ranging from 3×10 13 to 3×1014 ions/cm 2 and at 75o with respect ...
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Nanocrystalline tin oxide (SnO2) thin films were fabricated using pulsed laser deposition (PLD) technique. The as-deposited films were irradiated at liquid nitrogen (LN2) temperature using 100 MeV Ag ions at different fluences ranging from 3×10 13 to 3×1014 ions/cm 2 and at 75o with respect to surface normal. Pristine and irradiated samples were characterized using XRD, AFM, Raman and I-V (current-voltage characteristics) for the study of modifications in structural, surface morphological, bond angle and resistivity respectively. XRD patterns show that the pristine film is highly polycrystalline and irradiation amorphizes the film systematically with increasing the irradiation fluence. The surface of the pristine film contains nanograins of tin oxide with roughness 5.2 nm. Upon irradiation at lower fluences agglomeration is seen and roughness increased to 10.8 nm. Highest fluence irradiation again develops nanograins with roughness 7.5 nm. Raman spectra and I-V characteristics also confirms the irradiation induced amorphization. The observed results are explained in the frame work of thermal spike model.
Indra Sulania; Ambuj Tripathi; D. Kabiraj; Matthieu Lequeux; Devesh Avasthi
Abstract
In the present study, Indium Phosphide (InP) (100) samples with a thickness of ~ 0.5 mm have been bombarded with 1.5 keV Argon atoms for a fixed fluence of 8 × 10 16 atoms/cm 2 . The angle of incidence of the atom beam has been varied from normal incidence to 76° with respect to surface normal. ...
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In the present study, Indium Phosphide (InP) (100) samples with a thickness of ~ 0.5 mm have been bombarded with 1.5 keV Argon atoms for a fixed fluence of 8 × 10 16 atoms/cm 2 . The angle of incidence of the atom beam has been varied from normal incidence to 76° with respect to surface normal. The bombarded surface shows the nanostructures as analysed by Atomic Force Microscopy (AFM). For normal and near normal incident angles of the beam, nanodots pattern have been observed and after a critical angle of incidence, the dots begin to align and with further increase of angle, nanostructures elongate along the beam direction. At 63° incidence, a well ordered ripple pattern has been reported. The evolution of nanostructures from nanodots to nanoripples has been analysed in terms of their size, shape and roughness by means of AFM imaging.