@article{favela_zhang_cabral_ho_kim_das_porter_2022, title={Effects of Annealing on Co/Au and Ni/Au Schottky Contacts on beta-Ga2O3}, ISSN={["1543-186X"]}, DOI={10.1007/s11664-022-10151-6}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Favela, Elizabeth V and Zhang, Kun and Cabral, Matthew J. and Ho, Alice and Kim, Sun Ho and Das, Kalyan K. and Porter, Lisa M.}, year={2022}, month={Dec} }
 @article{mukhopadhyay_lyle_pal_das_porter_sarkar_2022, title={Evidence of thermionic emission in forward biased beta-Ga2O3 Schottky diodes at Boltzmann doping limit}, volume={131}, ISSN={["1089-7550"]}, DOI={10.1063/5.0068211}, abstractNote={A near-ideal and homogeneous β-Ga2O3 Schottky diode with Co contact for a doping level of ∼4.2 × 1017 cm−3 in the drift layer where the Boltzmann approximation is valid is reported. Unlike Si or GaN, thermionic emission is shown to be the dominant current conduction mechanism in the β-Ga2O3 Schottky diode at this doping level. A wide depletion region appended with a large built-in potential is observed to limit the thermionic field emission current, which is otherwise evident in narrower bandgap semiconductor (such as Si or GaN) Schottky diodes having a similar carrier concentration in the drift region. The results shown in this study can be used to identify the theoretical limits of drift layer doping beyond which the ideality factor and reverse leakage current should start deteriorating in ultra-wide bandgap semiconductor based Schottky diodes.}, number={2}, journal={JOURNAL OF APPLIED PHYSICS}, author={Mukhopadhyay, Swarnav and Lyle, Luke A. M. and Pal, Hridibrata and Das, Kalyan K. and Porter, Lisa M. and Sarkar, Biplab}, year={2022}, month={Jan} }
 @article{lyle_jiang_favela_das_popp_galazka_wagner_porter_2021, title={Effect of metal contacts on (100) beta-Ga2O3 Schottky barriers}, volume={39}, ISSN={["1520-8559"]}, DOI={10.1116/6.0000877}, abstractNote={The Schottky barriers of Ti, Mo, Co, Ni, Pd, and Au on (100) β-Ga2O3 substrates were analyzed using a combination of current-voltage (J-V), capacitance-voltage (C-V), and current-voltage-temperature (J-V-T) measurements. Near-ideal, average ideality factors for Ti, Mo, Co, and Ni were 1.05–1.15, whereas higher ideality factors (∼1.3) were observed for Pd and Au contacts. Barrier heights ranging from 0.60 to 1.20 eV were calculated from J-V measurements for the metals with low ideality factors. C-V measurements of all Schottky metals were conducted and yielded average barrier heights ranging from 0.78 to 1.98 eV. J-V-T measurements of Ti and Co diodes yielded barrier heights of 0.81 and 1.35 eV, respectively. The results reveal a strong positive correlation between the calculated Schottky barrier heights and the metal work functions: the index of interface behavior, S = 0.70, 0.97, and 0.81 for J-V, C-V, and J-V-T data, respectively.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Lyle, Luke A. M. and Jiang, Kunyao and Favela, Elizabeth V. and Das, Kalyan and Popp, Andreas and Galazka, Zbigniew and Wagner, Guenter and Porter, Lisa M.}, year={2021}, month={May} }
 @article{jadhav_lyle_xu_das_porter_sarkar_2021, title={Temperature dependence of barrier height inhomogeneity in beta-Ga2O3 Schottky barrier diodes}, volume={39}, ISSN={["2166-2754"]}, DOI={10.1116/6.0001059}, abstractNote={From an analysis of Pd contact Schottky diodes fabricated on (100) β-Ga2O3 wafers, in combination with data extracted from published work, we show that the barrier height inhomogeneity commonly observed in β-Ga2O3 Schottky diodes has a strong correlation to the temperature. For doping of ∼5 × 1017 cm−3, the barrier height arising from an inhomogeneous contact continues to increase to a temperature of ∼440 K followed by a decrease upon a further increase in temperature, which is commonly attributed to the bandgap narrowing of the semiconductor referred to as the Varshni shift. At this regime, Schottky characteristics representing close to homogeneous behavior is obtained. Thus, a device under normal operating conditions in a system, which results in an elevated temperature, is expected to exhibit near-homogeneous electrical characteristics.}, number={4}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Jadhav, Aakash and Lyle, Luke A. M. and Xu, Ziyi and Das, Kalyan K. and Porter, Lisa M. and Sarkar, Biplab}, year={2021}, month={Jul} }
 @article{lyle_jiang_das_porter_2019, title={Schottky contacts to beta-Ga2O3}, ISBN={["978-0-12-814521-0"]}, DOI={10.1016/B978-0-12-814521-0.00011-7}, abstractNote={This chapter reviews published literature on Schottky contacts to β-Ga2O3, a wide band gap semiconductor that has a low predicted on-resistance—a key performance advantage for high power Schottky diodes. Following a brief discussion of the general physics associated with the formation and measurement of metal–semiconductor Schottky barriers, reports on different Schottky contact metals (e.g., Au, Cu, Ir, Ni, Pd, and Pt) to β-Ga2O3 are summarized. Most of the reported contacts were fabricated directly on β-Ga2O3 single-crystal wafer surfaces, with one of the following crystallographic orientations: (010), (100), or (001). Details about the substrate surface preparation prior to metal deposition, and contact processing treatments are provided when available. The Schottky barrier heights are typically reported in the range ~ 1.0–1.5 eV and often show limited dependence on the metal work function, although there may be some dependence on factors such as crystal orientation. Both point and extended defects in Ga2O3 have been identified, but their effects on Schottky contacts are at the very early stage of investigation. Ga2O3 Schottky barrier diodes with Eb > 1 kV, and depletion-mode MESFETs, represent early devices that employ Schottky contacts.}, journal={GALLIUM OXIDE: TECHNOLOGY, DEVICES AND APPLICATIONS}, author={Lyle, Luke A. M. and Jiang, Lai and Das, Kalyan K. and Porter, Lisa M.}, year={2019}, pages={231–261} }
 @article{korivi_nujhat_ahmed_jiang_das_2018, title={Low-temperature deposition of polycrystalline germanium on silicon by magnetron sputtering}, volume={54}, ISSN={["1350-911X"]}, DOI={10.1049/el.2018.1291}, abstractNote={A new method is reported to grow polycrystalline germanium (Ge) on silicon (Si) at low temperatures by direct current magnetron sputtering. The method is based on first sputtering a nanometre scale thickness Si layer on a Si substrate, followed by sputtering a Ge layer of the desired thickness. Using this approach, polycrystalline Ge has been deposited on Si substrate at 300°C, the lowest reported process temperature for polycrystalline Ge on Si by sputter coating. Characterisation by X-ray diffraction and Raman spectroscopy showed polycrystalline Ge in the presence of a Si interfacial layer. In the absence of the interfacial Si layer, amorphous Ge was obtained under the same process conditions. These observations indicate that depositing a Si interfacial layer helps in improving the Ge film quality in low-temperature deposition conditions. The approach developed here makes it possible to achieve post-CMOS integration in applications that have low thermal budget, such as flexible electronics based on Si/Ge devices. The increased process flexibility offered by this method is also expected to enable new applications.}, number={17}, journal={ELECTRONICS LETTERS}, author={Korivi, N. and Nujhat, N. and Ahmed, S. and Jiang, L. and Das, K.}, year={2018}, month={Aug}, pages={1043-+} }