Bhubesh Chander Joshi
@jiit.ac.in
Assistant Professor PMSE
Jaypee Institute of Information Technology
RESEARCH, TEACHING, or OTHER INTERESTS
Electrical and Electronic Engineering, Materials Science
Scopus Publications
Scopus Publications
Prateek Gupta and Bhubesh C. Joshi
Elsevier BV
Prateek Gupta and B.C. Joshi
Elsevier BV
Prateek Gupta and Bhubesh C. Joshi
Springer Science and Business Media LLC
Prateek Gupta and Bhubesh C. Joshi
Springer Science and Business Media LLC
Bhubesh Chander Joshi
Walter de Gruyter GmbH
Abstract AlGaN/GaN heterostructures are one of the most promising semiconducting structures for fabricating high-speed and high-power electronic devices such as high electron mobility transistors and heterojunction bipolar transistors. Due to the lack of native substrates, these epitaxial structures are generally grown on foreign substrate materials such as sapphire, SiC and Si by using two-step growth techniques. In this paper, a few test structures along with TLM pads, FET structure, ohmic contacts and Schottky contacts have been fabricated on AlGaN/GaN heterostructure by photolithography, reactive ion etching, and e-beam metallization. Transmission line measurement has been used to calculate the sheet resistivity and contact resistance of ohmic pads. Current voltage measurement is used to test an FET structure of size 1 × 150 µm2 with a gate length of 4 µm and source to drain spacing of 5 µm.
Prateek Gupta and B. C. Joshi
Springer Science and Business Media LLC
Navneet K. Sharma and B.C. Joshi
Elsevier BV
B. C. Joshi, Alok P. S. Chauhan, Navneet K. Sharma, and Dinesh Tripathi
Springer Science and Business Media LLC
Vanita Devi, Himanshu Pandey, D. Tripathi, Manish Kumar, and B. C. Joshi
AIP Publishing
The optical and electrical properties of pristine and Al doped ZnO thin films on quartz substrate deposited using pulsed laser deposition (PLD) technique were studied. Photoluminescence (PL) study shows that emission peak shifts towards lower wavelength, which confirms that band gap increases using Al doping. 3% and 6% Al doped ZnO films shows n-type behavior with 19.2 cm2/Vs and 9.59 cm2/Vs hall mobility. Carrier concentration and electrical resistivity of 3% and 6% Al doped films were −7.588 x 10+20 cm−3, 0.0004274 Ohm-cm and 28.75 cm−3, 0.0005749 Ohm- cm respectively.
Himanshu Pandey, S. Chhoker, B. C. Joshi, and D. Tripathi
AIP Publishing
Adarsh Kumar Chaudhary, Vanita Devi, Karmvir Singh, B. C. Joshi, and Rakesh Dhar
Author(s)
Karmvir Singh, Vanita Devi, B. C. Joshi, and Rakesh Dhar
Author(s)
Structural, electronic and electrical properties of Phosphorus doped ZnO thin films deposited using pulsed laser deposition technique, on P-type Si (111) substrate are studied. X-ray diffraction measurements shows that undoped ZnO and Phosphorus doped ZnO films oriented along c-axis and maintains wurtzite crystalline symmetry. The change in grain size occurs by Phosphorus doping, which can be correlated to stress comes due to presence of Phosphorus. The changes in electronic structure has been observed by Phosphorus doping in ZnO thin films, which is understood from X-ray absorption spectroscopy. Hall measurements shows n-type behavior of Phosphorus doped ZnO samples.Structural, electronic and electrical properties of Phosphorus doped ZnO thin films deposited using pulsed laser deposition technique, on P-type Si (111) substrate are studied. X-ray diffraction measurements shows that undoped ZnO and Phosphorus doped ZnO films oriented along c-axis and maintains wurtzite crystalline symmetry. The change in grain size occurs by Phosphorus doping, which can be correlated to stress comes due to presence of Phosphorus. The changes in electronic structure has been observed by Phosphorus doping in ZnO thin films, which is understood from X-ray absorption spectroscopy. Hall measurements shows n-type behavior of Phosphorus doped ZnO samples.
Vanita Devi, Manish Kumar, Ravindra Kumar, Amanpal Singh, and B C Joshi
IOP Publishing
Accurate knowledge of the alignment of conduction and valence bands of layers at the heterojunction and warrant knowledge of the band offsets at the interface is essential for Zn1−xSbxO/ZnO based quantum well device designing and modeling. Under this scenario, valence band offsets of Zn1−xSbxO/ZnO heterostructures grown by the pulsed laser deposition technique was measured by photoelectron spectroscopy and consequently, the conduction band offset was calculated by UV-visible spectroscopy. The change in band alignment has been observed with the dopant (Sb) concentration. Ratios of conduction band offset to valence band offset were estimated to be 1.67 and 0.04 for x = 0.03 and 0.06, respectively, for Sb doped films. A Type-II band alignment was observed at the Zn0.97Sb0.03O/ZnO interface, whereas the Type-I band alignment took place at the Zn0.94Sb0.06O/ZnO interface.
Vanita Devi, Manish Kumar, D.K. Shukla, R.J. Choudhary, D.M. Phase, Ravindra Kumar, and B.C. Joshi
Elsevier BV
Vanita Devi, Manish Kumar, A. D. Wadikar, R. J. Choudhary, D. M. Phase, and B. C. Joshi
AIP Publishing LLC
Thin film sample of Zn0.85Mg0.15O was prepared on Si (100) substrate by pulsed laser deposition and its structural, electronic, magnetic and ferroelectric properties were investigated. The Zn0.85Mg0.15O thin film sample is found to show room temperature multiferroic properties; suitable for device fabrication.
Vanita Devi, Manish Kumar, R. J. Choudhary, D. M. Phase, Ravindra Kumar, and B. C. Joshi
AIP Publishing
The valence and conduction band offsets of Zn1−xCdxO/ZnO hetero-junctions deposited by pulsed laser deposition technique were estimated by X-ray photoelectron, valence band, and UV-visible spectroscopy. Type-II band alignment (staggered gap) with ratios of conduction band to valence band offsets (ΔEC/ΔEV) was found to be 0.77 and 0.59 for Zn0.95Cd0.05O/ZnO and Zn0.90Cd0.10O/ZnO hetero-structures, respectively, which can be used in longer wavelength regime optoelectronic devices. The higher value of valence band offset as compared to conduction band offset suggests that the transport at interface is mainly due to electrons.
Vanita Devi, Manish Kumar, Ravindra Kumar, and B.C. Joshi
Elsevier BV
Vanita Devi, Manish Kumar, R. J. Choudhary, and B. C. Joshi
AIP Publishing LLC
Thin films of Zn1-xCdxO (x=0, 0.05, 0.1) were deposited on glass substrate by pulsed laser deposition technique. The structural and optical properties of the prepared thin film samples were investigated using X-Ray Diffraction (XRD), Atomic force Microscopy, UV-visible and Photoluminescence spectroscopy. XRD results confirm that deposited films were oriented along c-axis and contain wurtzite crystalline symmetry. XRD and AFM result reveled that, the grain size decreases with increasing Cd concentration. UV-visible spectroscopy results reveal high transmittance for all the thin film samples. A reduction in the optical band gap energy with increasing Cd composition was observed through the Tauc plot method.
Vanita Devi, Ravindra Kumar, and B. C. Joshi
Institute of Electrical and Electronics Engineers (IEEE)
-Polarization doping in quantum wells and electron blocking layer is proposed to improve the emission intensity and efficiency droop of InGaN light-emitting diodes (LEDs). Band diagrams and the internal quantum efficiencies of LEDs are theoretically studied by the ATLAS simulation program. Numerical results show that the internal quantum efficiency of polarization doped LED structures are improved by 25% as compared to un-doped structures which can be due to accumulation of high density two-dimensional electron gas in quantum wells.
Vanita Devi, B C Joshi, Manish Kumar, and R J Choudhary
IOP Publishing
The 7 wt % Cd doped and 15 wt % Mg doped ZnO thin films were deposited on quartz substrate by pulse laser deposition system. The structural and optical properties of the prepared ZnO, Cd:ZnO and Mg:ZnO films were investigated by X-Ray diffraction (XRD), photoluminescence and UV-Vis spectroscopy techniques. XRD results indicate that the doped ZnO films maintain wurtzite crystal symmetry without any defects and are oriented along c- axis. Photoluminescence studies show a sharp band edge emission peak at 384 nm for pure ZnO film. This peak is blue shifted to 381 nm with Cd doping and red shifted to 395 nm with Mg doping. UV visible absorption studies reveals a decrease in band gap with Cd doping and an increase in band gap with Mg doping.
G. Srivani Padma, Sumitra Singh, Manish Mathew, Kuldip Singh, B. C. Joshi, Surjit Das, and C. Dhanavantri
Springer Science and Business Media LLC
William R. Taube, A. Kumar, R. Saravanan, P.B. Agarwal, P. Kothari, B.C. Joshi, and D. Kumar
Elsevier BV
Amanpal Singh, Dinesh Kumar, P.K. Khanna, Bhubesh Chander Joshi, and Mukesh Kumar
Elsevier BV