Publications
2025
Micro-X-ray-CT for analysis of particle size segregation during powder spreading in Binder Jet Printing
Behnsen, J. G., Roberts, J. W., Rogan, O. J., McArdle, J. M., & Black, K. (2025). Micro-X-ray-CT for analysis of particle size segregation during powder spreading in Binder Jet Printing. Additive Manufacturing Letters, 100266. doi:10.1016/j.addlet.2024.100266
2024
Atomic scale observation of threading dislocations in <i>α</i>-Ga2O3
Mullen, R., Roberts, J. W., Chalker, P. R., Oliver, R. A., Hourahine, B., & Massabuau, F. C. P. (2024). Atomic scale observation of threading dislocations in <i>α</i>-Ga2O3. AIP Advances, 14(11). doi:10.1063/5.0235005
Constant Photocurrent Method to Probe the Sub‐Bandgap Absorption in Wide Bandgap Semiconductor Films: The Case of α‐Ga<sub>2</sub>O<sub>3</sub>
Nicol, D., Reynolds, S., Barr, K., Roberts, J. W., Jarman, J. J., Chalker, P. R., & Massabuau, F. C. (2024). Constant Photocurrent Method to Probe the Sub‐Bandgap Absorption in Wide Bandgap Semiconductor Films: The Case of α‐Ga<sub>2</sub>O<sub>3</sub>. physica status solidi (b). doi:10.1002/pssb.202300470
2023
Ni/Au contacts to corundum <i>α</i>-Ga<sub>2</sub>O<sub>3</sub>
Massabuau, F. C. -P., Adams, F., Nicol, D., Jarman, J. C., Frentrup, M., Roberts, J. W., . . . Oliver, R. A. (2023). Ni/Au contacts to corundum <i>α</i>-Ga<sub>2</sub>O<sub>3</sub>. JAPANESE JOURNAL OF APPLIED PHYSICS, 62(SF). doi:10.35848/1347-4065/acbc28
Redshift and amplitude increase in the dielectric function of corundum-like α-(Ti<sub><i>x</i></sub>Ga<sub>1-<i>x</i></sub>)<sub>2</sub>O<sub>3</sub>
Kluth, E., Fay, M., Parmenter, C., Roberts, J., Smith, E., Stoppiello, C., . . . Feneberg, M. (2023). Redshift and amplitude increase in the dielectric function of corundum-like α-(Ti<sub><i>x</i></sub>Ga<sub>1-<i>x</i></sub>)<sub>2</sub>O<sub>3</sub>. APPLIED PHYSICS LETTERS, 122(9). doi:10.1063/5.0139725
Hydrogen-related 3.8 eV UV luminescence in <i>α</i>-Ga<sub>2</sub>O<sub>3</sub>
Nicol, D., Oshima, Y., Roberts, J. W., Penman, L., Cameron, D., Chalker, P. R., . . . Massabuau, F. C. -P. (2023). Hydrogen-related 3.8 eV UV luminescence in <i>α</i>-Ga<sub>2</sub>O<sub>3</sub>. APPLIED PHYSICS LETTERS, 122(6). doi:10.1063/5.0135103
2021
Study of Ti contacts to corundum α-Ga2O3
Massabuau, F., Nicol, D., Adams, F., Jarman, J., Roberts, J., Kovacs, A., . . . Oliver, R. (n.d.). Study of Ti contacts to corundum α-Ga2O3. Journal of Physics D: Applied Physics. doi:10.1088/1361-6463/ac0d28
Progress in atomic layer deposited [alpha]-Ga2O3 materials and solar-blind detectors
Massabuau, F., Roberts, J. W., Nicol, D., Edwards, P. R., McLelland, M., Dallas, G. L., . . . Chalker, P. R. (2021). Progress in atomic layer deposited [alpha]-Ga2O3 materials and solar-blind detectors. In F. H. Teherani, D. C. Look, & D. J. Rogers (Eds.), Oxide-based Materials and Devices XII (pp. 20). SPIE. doi:10.1117/12.2588729
2020
Ti Alloyed α-Ga2O3: Route towards Wide Band Gap Engineering
Barthel, A., Roberts, J., Napari, M., Frentrup, M., Huq, T., Kovács, A., . . . Massabuau, F. (n.d.). Ti Alloyed α-Ga2O3: Route towards Wide Band Gap Engineering. Micromachines, 11(12), 1128. doi:10.3390/mi11121128
Modelling of metallic particle binders for increased part density in binder jet printed components
Roberts, J. W., Sutcliffe, C. J., Green, P. L., & Black, K. (2020). Modelling of metallic particle binders for increased part density in binder jet printed components. ADDITIVE MANUFACTURING, 34. doi:10.1016/j.addma.2020.101244
Influence of Polymorphism on the Electronic Structure of Ga<sub>2</sub>O<sub>3</sub>
Swallow, J. E. N., Vorwerk, C., Mazzolini, P., Vogt, P., Bierwagen, O., Karg, A., . . . Regoutz, A. (2020). Influence of Polymorphism on the Electronic Structure of Ga<sub>2</sub>O<sub>3</sub>. CHEMISTRY OF MATERIALS, 32(19), 8460-8470. doi:10.1021/acs.chemmater.0c02465
(Invited) Band Line-up of High-k Oxides on GaN
Mitrovic, I. Z., Das, P., Jones, L., Gibbon, J., Dhanak, V. R., Mahapatra, R., . . . Thayne, I. G. (2020). (Invited) Band Line-up of High-k Oxides on GaN. ECS Transactions, 97(1), 67-81. doi:10.1149/09701.0067ecst
Band Line-up Investigation of Atomic Layer Deposited TiAlO and GaAlO on GaN
Das, P., Jones, L. A. H., Gibbon, J. T., Dhanak, V. R., Partida-Manzanera, T., Roberts, J. W., . . . Mitrovic, I. Z. (2020). Band Line-up Investigation of Atomic Layer Deposited TiAlO and GaAlO on GaN. ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY, 9(6). doi:10.1149/2162-8777/aba4f4
2019
Low temperature growth and optical properties of alpha-Ga2O3 deposited on sapphire by plasma enhanced atomic layer deposition
Roberts, J. W., Chalker, P. R., Ding, B., Oliver, R. A., Gibbon, J. T., Jones, L. A. H., . . . Massabuau, F. C. -P. (2019). Low temperature growth and optical properties of alpha-Ga2O3 deposited on sapphire by plasma enhanced atomic layer deposition. JOURNAL OF CRYSTAL GROWTH, 528. doi:10.1016/j.jcrysgro.2019.125254
Modelling of Metallic Particle Binders for Increased Part Density in Binder Jet Printed Components
Roberts, J., Green, P., Black, K., & Sutcliffe, C. (2019). Modelling of Metallic Particle Binders for Increased Part Density in Binder Jet Printed Components. doi:10.20944/preprints201911.0064.v1
Comparison of atomic layer deposited Al<sub>2</sub>O<sub>3</sub> and (Ta<sub>2</sub>O<sub>5</sub>)<sub>0.12</sub>(Al<sub>2</sub>O<sub>3</sub>)<sub>0.88</sub> gate dielectrics on the characteristics of GaN-capped AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors
Partida-Manzanera, T., Zaidi, Z. H., Roberts, J. W., Dolmanan, S. B., Lee, K. B., Houston, P. A., . . . Potter, R. J. (2019). Comparison of atomic layer deposited Al<sub>2</sub>O<sub>3</sub> and (Ta<sub>2</sub>O<sub>5</sub>)<sub>0.12</sub>(Al<sub>2</sub>O<sub>3</sub>)<sub>0.88</sub> gate dielectrics on the characteristics of GaN-capped AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors. JOURNAL OF APPLIED PHYSICS, 126(3). doi:10.1063/1.5049220
Effect of HCl cleaning on InSb-Al2O3 MOS capacitors
Vavasour, O. J., Jefferies, R., Walker, M., Roberts, J. W., Meakin, N. R., Gammon, P. M., . . . Ashley, T. (2019). Effect of HCl cleaning on InSb-Al2O3 MOS capacitors. SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 34(3). doi:10.1088/1361-6641/ab0331
2018
Band alignments at Ga<sub>2</sub>O<sub>3</sub> heterojunction interfaces with Si and Ge
Gibbon, J. T., Jones, L., Roberts, J. W., Althobaiti, M., Chalker, P. R., Mitrovic, I. Z., & Dhanak, V. R. (2018). Band alignments at Ga<sub>2</sub>O<sub>3</sub> heterojunction interfaces with Si and Ge. AIP ADVANCES, 8(6). doi:10.1063/1.5034459
Band alignments at Ga2O3 heterojunction interfaces with Si and Ge
Gibbon, J. T., Jones, L., Roberts, J. W., Althobaiti, M., Chalker, P. R., Mitrovic, I. Z., & Dhanak, V. R. (2018). Band alignments at Ga2O3 heterojunction interfaces with Si and Ge. AIP Advances, 8(6). doi:10.1063/1.5034459
Effects of surface plasma treatment on threshold voltage hysteresis and instability in metal-insulator-semiconductor (MIS) AlGaN/GaN heterostructure HEMTs
Zaidi, Z. H., Lee, K. B., Roberts, J. W., Guiney, I., Qian, H., Jiang, S., . . . Houston, P. A. (2018). Effects of surface plasma treatment on threshold voltage hysteresis and instability in metal-insulator-semiconductor (MIS) AlGaN/GaN heterostructure HEMTs. JOURNAL OF APPLIED PHYSICS, 123(18). doi:10.1063/1.5027822
alpha-Ga2O3 grown by low temperature atomic layer deposition on sapphire
Roberts, J. W., Jarman, J. C., Johnstone, D. N., Midgley, P. A., Chalker, P. R., Oliver, R. A., & Massabuau, F. C. -P. (2018). alpha-Ga2O3 grown by low temperature atomic layer deposition on sapphire. JOURNAL OF CRYSTAL GROWTH, 487, 23-27. doi:10.1016/j.jcrysgro.2018.02.014
Elucidation of ALD MgZnO deposition processes using low energy ion scattering
Werner, M., Roberts, J. W., Potter, R. J., Dawson, K., & Chalker, P. R. (2018). Elucidation of ALD MgZnO deposition processes using low energy ion scattering. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 36(2). doi:10.1116/1.5015958
2017
Atomic layer deposition of niobium nitride from different precursors
Pizzol, P., Roberts, J. W., Wrench, J., Malyshev, O. B., Valizadeh, R., & Chalker, P. R. (2017). Atomic layer deposition of niobium nitride from different precursors. In IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference (pp. 1094-1097).
2016
Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics
Roberts, J., Chalker, P., Lee, K. B., Houston, P., Cho, S. J., Thayne, I., . . . Humphreys, C. (2016). Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics. Applied Physics Letters, 108(7). doi:10.1063/1.4942093
Comparative analysis of the effects of tantalum doping and annealing on atomic layer deposited (Ta<sub>2</sub>O<sub>5</sub>)<i><sub>x</sub></i>(Al<sub>2</sub>O<sub>3</sub>)<sub>1-<i>x</i></sub> as potential gate dielectrics for GaN/Al<i><sub>x</sub></i>Ga<sub>1-<i>x</i></sub>N/GaN high electron mobility transistors
Partida-Manzanera, T., Roberts, J. W., Bhat, T. N., Zhang, Z., Tan, H. R., Dolmanan, S. B., . . . Potter, R. J. (2016). Comparative analysis of the effects of tantalum doping and annealing on atomic layer deposited (Ta<sub>2</sub>O<sub>5</sub>)<i><sub>x</sub></i>(Al<sub>2</sub>O<sub>3</sub>)<sub>1-<i>x</i></sub> as potential gate dielectrics for GaN/Al<i><sub>x</sub></i>Ga<sub>1-<i>x</i></sub>N/GaN high electron mobility transistors. JOURNAL OF APPLIED PHYSICS, 119(2). doi:10.1063/1.4939298
2015
Electrical Properties and Interfacial Studies of Hf<i><sub>x</sub></i>Ti<sub>1-<i>x</i></sub>O<sub>2</sub> High Permittivity Gate Insulators Deposited on Germanium Substrates
Lu, Q., Mu, Y., Roberts, J. W., Althobaiti, M., Dhanak, V. R., Wu, J., . . . Chalker, P. R. (2015). Electrical Properties and Interfacial Studies of Hf<i><sub>x</sub></i>Ti<sub>1-<i>x</i></sub>O<sub>2</sub> High Permittivity Gate Insulators Deposited on Germanium Substrates. MATERIALS, 8(12), 8169-8182. doi:10.3390/ma8125454
A study of the impact of in-situ argon plasma treatment before atomic layer deposition of Al<sub>2</sub>O<sub>3</sub> on GaN based metal oxide semiconductor capacitor
Cho, S. J., Roberts, J. W., Guiney, I., Li, X., Ternent, G., Floros, K., . . . Thayne, I. G. (2015). A study of the impact of in-situ argon plasma treatment before atomic layer deposition of Al<sub>2</sub>O<sub>3</sub> on GaN based metal oxide semiconductor capacitor. MICROELECTRONIC ENGINEERING, 147, 277-280. doi:10.1016/j.mee.2015.04.067
2013
Atomic layer deposition of Ga-doped ZnO transparent conducting oxide substrates for CdTe-based photovoltaics
Chalker, P. R., Marshall, P. A., Romani, S., Roberts, J. W., Irvine, S. J. C., Lamb, D. A., . . . Williams, P. A. (2013). Atomic layer deposition of Ga-doped ZnO transparent conducting oxide substrates for CdTe-based photovoltaics. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 31(1). doi:10.1116/1.4765642
Undated
Synthesis and characterisation of nanoscale oxides for energy applications
Roberts, J. (n.d.). Synthesis and characterisation of nanoscale oxides for energy applications. (PhD Thesis, University of Liverpool).