Dr Ranjit Sarma
@info@ckbcc.org
Principal
C.K.B. Commerce College
RESEARCH INTERESTS
Thin Film Physics, OTFT, OLED
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Tribeni Borthakur and Ranjit Sarma
Springer Science and Business Media LLC
Tribeni Borthakur and Ranjit Sarma
The Electrochemical Society
Top-contact pentacene-based organic thin-film transistor (OTFT) with a rubrene interlayer in between pentacene-electrode [Al, Au] interface is reported. A study of the interlayer behavior of rubrene shows enhanced device performance of OTFT than that of the conventional OTFTs with only metal source-drain electrodes [Al, Au]. The improved performances of the device are attributed to the smoother pentacene surface for high carrier injection and mobility and decrease in contact resistance of the device. The device with a rubrene interlayer in between pentacene/Au interface shows better field-effect mobility of 3.3 cm2 v−1 s−1, On/Off ratio of 1.22 × 107, the threshold voltage of −3.8 V, and sub-threshold-slope of 0.31 V decade−1 respectively.
Sagarika Khound, Jayanta K Sarmah, and Ranjit Sarma
The Electrochemical Society
In this work, we have studied the electrical performance of cross-linked polyvinyl phenol (cPVP) modified lanthanum oxide (La2O3) bilayer dielectric film in pentacene thin film transistors (TFT). A simple spin-coating and room temperature operated cross-linking reaction of the hydroxyl moieties of PVP and the nitrogen groups of PMF were carried out to form the cross-linked PVP. The deposition of a thin 30 nm cPVP layer over the La2O3 layer provided a low leakage current (<10−7 A cm−2), causing a reduction in the interface trap density. Besides, the modified surface properties of the La2O3 layer were favorable for the growth of pentacene organic semiconductors. As a result, the current on-off ratio and the sub-threshold slope was improved from 104 and 1.0 V/decade to 105 and 0.67 V/decade. The La2O3∕cPVP pentacene TFT operated at −10 V also exhibited improvement in the field-effect mobility to 0.71 cm2 Vs−1 from 0.48 cm2 Vs−1 for the single-layer La2O3 (130 nm) device. Thus, our work demonstrates that the rare earth oxide La2O3 with cPVP is an excellent dielectric system in the context of emerging transistors with hybrid polymer gate dielectrics.
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Sagarika Khound and Ranjit Sarma
Springer Science and Business Media LLC
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Sagarika Khound and Ranjit Sarma
Springer Science and Business Media LLC
Dhrubajyoti Saikia and Ranjit Sarma
Springer Science and Business Media LLC
Tribeni Borthakur and Ranjit Sarma
Springer Science and Business Media LLC
D Saikia and R Sarma
Springer Science and Business Media LLC
Tribeni Borthakur and Ranjit Sarma
Springer Science and Business Media LLC
Tribeni Borthakur and Ranjit Sarma
Springer Science and Business Media LLC
Ranjit Sarma and Dipok Saikia
Institute of Electrical and Electronics Engineers (IEEE)
MoO<sub>3</sub> prepared by oxidizing a Mo filament (oxidized MoO<sub>3</sub>) with Al is a good replacement of a Au electrode for pentacene-based organic thin-film transistors (TFTs) (OTFTs). The oxidized MoO<sub>3</sub>/Al bilayer electrode shows better result than the laboratory-prepared pure MoO<sub>3</sub>/Al bilayer electrode. This process will save the cost of laboratory-prepared pure MoO<sub>3</sub>. The OTFTs show a very good current on-off ratio of 1.6 × 10<sup>6</sup> and a field-effect mobility (μ) of 0.57 cm<sup>2</sup>/V·s. With this process, we can fabricate low-cost pentacene TFTs with better performance by using a very simple fabrication technique.
R. Sarma, D. Saikia, Puja Saikia, P.K. Saikia, and B. Baishya
FapUNIFESP (SciELO)
We have investigated the pentacene based Organic Thin Film Transistors (OTFTs) with High-k Dielectric Nd2O3. Use of high dielectric constant (high-k) gate insulator Nd2O3 reduces the threshold voltage and sub threshold swing of the OTFTs. The calculated threshold voltage -2.2V and sub-threshold swing 1V/decade, current ON-OFF ratio is 1.7 × 104 and mobility is 0.13cm2/V.s. Pentacene film is deposited on Nd2O3 surface using two step deposition method. Deposited pentacene film is found poly crystalline in nature.
R. Sarma, D. Saikia, K. Konwar, and B. Baishya
Springer Science and Business Media LLC