Publications
Under Review/Accepted:
Completed:
S. P. Watkins, S. Riahi, D. Lister, C. Lohn, K. Stirling, F. Mohammadbeigi, A. Dharbandi, E. Senthil Kumar, 鈥淏roadening mechanisms of donor bound exciton photoluminescence in Ga-doped ZnO nanowires, J. Appl. Phys. 136, 214302 (2024)
Anitha Jose, Sarry Al-Turk, Harry E. Ruda, Simon P. Watkins, Martha R. McCartney, Cristina Cordoba and Karen L. Kavanagh, 鈥淐omparing the mean inner potential of Zn-VI semiconductor nanowires using off-axis electron holography鈥, Semiconductor Science and Technology, Semicond. Sci. Technol. 39, 075004 (2024)
Maria L. K. Viitaniemi,* Christian Zimmermann, Vasileios Niaouris, Samuel H. D鈥橝mbrosia, Xingyi Wang, E. Senthil Kumar, Faezeh Mohammadbeigi, Simon P. Watkins, and Kai-Mei C. Fu, "Coherent Spin Preparation of Indium Donor Qubits in Single ZnO Nanowires", 22, 2134 (2022)
Mingze Yang, Ali Darbandi, S. P. Watkins, and K. L. Kavanagh, "Geometric effects on carrier collection in core-shell nanowire p-n junctions"
M. Hegde, F. Mohammadbeigi, T. Kure, E Senthil Kumar, M. R. Wagner, A. Hoffmann, and S.P. Watkins, 鈥淭riple group V donors in ZnO鈥,
Mingze Yang, David Dvorak, Karin Leistner, Christine Damm, Simon P. Watkins, and Karen L. Kavanagh, "Axial EBIC oscillations at core/shell GaAs/Fe nanowire contacts",
S.P. Watkins, F. Mohammadbeigi, K. Stirling, and E.S. Kumar, "Photoluminescence Excitation Spectroscopy of Antimony Donors in ZnO",
S. Alagha, S. Zhao, Z. Mi, S. P. Watkins and K. L.Kavanagh,"Electrical characterization of Si/InN nanowire heterojunctions"
S. Alagha, Sebastian Heedt, Daniel Vakulov, F. Mohammadbeigi, E. Senthil Kumar, Thomas Schaepers, Dieter Isheim, S.P. Watkins, K.L. Kavanagh, 鈥淐haracterization of Ga-doped ZnO nanowires",
D.J. Dvorak, A. Darbandi, K.L. Kavanagh, S.P. Watkins, "Regrowth mechanism for oxide isolation of GaAs nanowires" Nanotechnology, .
S. Alagha, A. Shik, H. E. Ruda, I. Saveliev, K. L. Kavanagh, and S. P. Watkins, 鈥淣umerical analysis of space-charge-limited current in nanowires鈥,
F. Mohammadbeigi, T. Kure, G. Callsen, E. Senthil Kumar, M.R. Wagner, A. Hoffmann, and S.P. Watkins, "Influence of carbon doping and hydrogen co-doping on acceptor related optical transitions in ZnO nanowires",
Todd Karin, Xiayu Linpeng, M.V. Durnev, Russell Barbour, M.M. Glazov, E.Ya. Sherman, Colin Stanley, S.P. Watkins, Satoru Seto, and Kai-Mei C. Fu, 鈥淟ongitudinal spin-relaxation of donor-bound electrons in direct bandgap semiconductors鈥, .
Ali Darbandi and S.P. Watkins, "Measurement of minority carrier diffusion lengths in GaAs nanowires by a nanoprobe technique",
Ali Darbandi, James McNeil, Azadeh Akhtari-Zavareh, S.P.Watkins, and Karen L. Kavanagh, 鈥淒irect Measurement of the Electrical Abruptness of a Nanowire p-n Junction鈥,
Mingze Yang, Ali Darbandi, S.P. Watkins, and Karen Kavanagh, 鈥淓pitaxial Fe on Free-standing GaAs Nanowires鈥,
E. Senthil Kumar, F. Mohammadbeigi, L. A. Boatner, and S. P. Watkins, "High-resolution photoluminescence spectroscopy of Sn-doped ZnO single crystals",
A. Darbandi, K. L. Kavanagh, and S. P. Watkins, 鈥淟ithography-free fabrication of core-shell GaAs nanowire tunnel diodes鈥,
F. Mohammadbeigi, E. Senthil Kumar, S. Alagha, I. Anderson and S. P. Watkins, "Carbon related donor bound exciton transitions in ZnO nanowires" J
A. Darbandi, O. Salehzadeh, P. Kuyanov, R. R. LaPierre, and S. P. Watkins, "Surface passivation of tellurium-doped GaAs nanowires by GaP: e铿ect on electrical conduction",
O. Salehzadeh, B. Cawston-Grant, S.P. Watkins, and P.M. Mooney, "Electrical Characterization of In-Place Bonded Interfaces",
P.M. Mooney, K.L. Kavanagh, D. Owen, D. Lackner, B. Cawston-Grant, A.F. Basile, O. Salehzadeh, and S.P. Watkins, "Characterization of solution-bonded GaAs/InGaAs/GaAs features on GaAs",
O. Salehzadeh, K. L. Kavanagh, and S. P. Watkins, Geometric limits of coherent III-V core/shell nanowires,
O. Salehzadeh, K. L. Kavanagh, and S. P. Watkins, "Growth and strain relaxation of GaAs and GaP nanowires with GaSb shells", J. Applied Phys.,
E. Senthil Kumar, F. Mohhamadbegi, D. Zeng, I. Anderson, T. Wintchel, and S. P. Watkins, "Optical evidence for donor behavior of Sb in ZnO nanowires", .
O. Salehzadeh, K. L. Kavanagh, and S. P. Watkins, "Growth and strain relaxation of GaAs (GaP)/GaSb core/shell nanowires", accepted in J. Applied Phys., Feb. 2013.
E. Senthil Kumar, I. Anderson, Z. Deng, F. Mohammadbeigi, T. Wintschel, D. Huang, S.P. Watkins, 鈥淓ffect of group-III donors on high resolution photoluminescence and microstructure of ZnO nanowires grown by metalorganic chemical vapor deposition鈥, .
S. Zhao, O. Salehzadeh, S. Alagha, K.L. Kavanagh, S.P. Watkins, and Z. Mi, "Probing the electrical transport properties of intrinsic InN nanowires",
O. Salehzadeh, X. Zhang, B.D. Gates, K.L. Kavanagh, S.P. Watkins, 鈥減-type doping of GaAs nanowires using carbon鈥, )
O. Salehzadeh, K.L. Kavanagh, and S.P Watkins, 鈥淐ontrolled axial and radial Te-doping of GaAs nanowires鈥, .
C. Liu, O. Salehzadeh, P. J. Poole, S. P. Watkins, and K. L. Kavanagh, 鈥淚nsights into semiconductor nanowire conductivity using electrodeposition鈥,
B. Kardasz, S. P. Watkins, E.A. Montoya, C.Burrowes, E. Girt, and B. Heinrich, 鈥淚nterface magnetism of iron grown on sulfur and hydrogen passivated GaAs(001)鈥,
D. Lackner, M. Steger, M.L.W. Thewalt, O. J. Pitts, Y.T. Cherng, and S.P. Watkins, E. Plis, and S Krishna, 鈥淚nAs/InAsSb strain balanced superlattices for optical detectors: materials properties and energy band simulations鈥,
O. Salehzadeh, M. X. Chen, K. L. Kavanagh, S. P. Watkins, 鈥淩ectifying characteristics of Te-doped GaAs nanowires鈥,
S.P. Watkins, Z.W. Deng, D.C. Li, He. Huang, "High resolution photoluminescence spectroscopy of donors in undoped and In-doped ZnO grown by metalorganic vapor phase epitaxy",
O. Salehzadeh, S.P. Watkins, "Control of GaAs nanowire morphology by group III precursor chemistry",
O. Salehzadeh, S.P. Watkins, 鈥淓ffect of carbon dopant on the morphology of GaAs nanowires鈥,
D. Lackner, M. Martine, Y. T. Cherng, M. Steger, W. Walukiewicz, M. L. W. Thewalt, P. M. Mooney, and S. P. Watkins, 鈥淓lectrical and optical characterization of n-InAsSb/n-GaSb heterojunctions鈥, .
He Huang, Z.W. Deng, D.C. Li, E. Barbir, W.Y. Jiang, M.X. Chen, K.L. Kavanagh, P.M. Mooney, S.P Watkins, "Effect of Annealing on Structural and Optical Properties of Heavily Carbon-Doped ZnO", Semicond. Sci. Technol. 25 (2010) 045023.
W.Y. Jiang, K.L. Kavanagh, S.P. Watkins, 鈥淕rowth mechanisms for atomic ordering in GaAsSb grown by MOVPE鈥 J. Cryst. Growth, 311, 4391 (2009)
D. Lackner, O.J. Pitts, M. Steger, A. Yang, M.L.W. Thewalt, S.P. Watkins, 鈥淪train balanced InAsSb/InAs superlattice structures with optical emission to 10 microns鈥
D. Lackner, O. J. Pitts, S. Najmi, P. Sandhu, K. L. Kavanagh, A. Yang, M. Steger, M. L. W. Thewalt, Y. Wang, D. W. McComb, C. R. Bolognesi, S. P. Watkins, 鈥淚nAsSb/InAs MQWs grown by MOCVD on GaSb for mid-IR photodetector applications鈥, J. Cryst. Growth, 311, 3563 (2009)
R.A. Rosenberg, M. Abu Haija, and S.P. Watkins, 鈥淴-ray and electron induced infrared emission spectroscopy鈥, Rev. Sci. Instruments. 80, 046104 (2009)
D.L. Owen, D. Lackner, O.J. Pitts, S.P. Watkins and P.M. Mooney, 鈥淚n Place Bonding of GaAs/InGaAs/GaAs Heterostructures to GaAs(001)鈥, Semicond. Sci. Technol. 24, 035011 (2009)
O.J. Pitts, D. Lackner, Y.T. Cherng, S.P. Watkins, 鈥淕rowth of InAsSb/InPSb heterojunctions for mid-IR detector applications鈥, J. Cryst. Growth, 310 4858 (2008).
D. Huang, W.Y. Jiang, S.P. Watkins, 鈥淔low modulation epitaxy of ZnO films on sapphire substrates鈥, J. Cryst. Growth 310, 4050 (2008)
S. Najmi, X.K. Chen, S.P. Watkins, 鈥淒icarbon defects in as-grown and annealed carbon doped InAs鈥, J. Appl. Phys. 102, 083528 (2007)
A.J. Clayton, A.A. Khandekar, T.F. Kuech, N.J. Mason, M.F. Robinson, S.P. Watkins, Y. Guo, 鈥淕rowth of AlN by vectored flow epitaxy鈥, J. Cryst. Growth, 298, 328 (2007).
K. Alberi, J. Wu, W. Walukiewicz, K.M. Yu, O.D. Dubon, S.P. Watkins , C.X. Wang, X. Liu, Y.-J. Cho, and J. Furdyna, 鈥淰alence band anticrossing in mismatched III-V semiconductor alloys鈥, Phys. Rev. B75, 045203 (2007).
K. Alberi, J. Wu, W. Walukiewicz, K. M. Yu, O. D. Dubon, S. P. Watkins, C. X. Wang, X. Liu, Y.-J. Cho, and J. K. Furdyna, 鈥淰alence band anticrossing in mismatched III-V semiconductor alloys鈥, Phys. Stat. Sol. (c) 4,1711 (2007)
H. G. Liu, D.W. DiSanto, S. P. Watkins, and C. R. Bolognesi, 鈥淚nP/GaAsSb/InP DHBTs with fT = 300 GHz and high maximum oscillation frequencies: the effect of scaling on device performance鈥, Phys. Stat. Sol.(c) 3, 4612 (2006)
Y. Guo, O. J. Pitts, W.Jiang, S.P. Watkins, 鈥淣umerical Optimization of an Optical Showerhead Reactor Design for Organometallic Vapor Phase Epitaxy鈥 J. Cryst. Growth, 297, 345 (2006)
S. Najmi, M.X. Chen, A. Yang, M. Steger, M.L.W. Thewalt, S.P. Watkins, 鈥淟ocal Vibrational Mode Study of Carbon Doped InAs鈥, Phys. Rev. B 74, 113202 (2006).
H.G. Liu, S.P. Watkins, and C.R. Bolognesi, 鈥15-nm base type-II InP/GaAsSb/InP DHBTs with Ft=384GHz and a 6-V BVCEO鈥, IEEE Transactions on Electron Devices, 53, 559 (2006).
S. Najmi, X. Zhang, X.K. Chen, M. L. W. Thewalt, S.P. Watkins, 鈥淩aman scattering in carbon-doped InAs鈥, Appl. Phys. Lett. 88, 041908 (2006).
W.Y. Jiang, J.Q. Liu, X. Zhang, M.L.W. Thewalt, K.L. Kavanagh, S.P. Watkins, 鈥淢icrostructure of ordered nanodomains induced by Bi surfactant in OMVPE-grown GaAsSb鈥 J. Cryst. Growth, 287, 541 (2006).
T.S. Rao, M.G. So, W.Jiang, T.Mayer, S. Roorda, S.C. Gujrathi, M.L.W.Thewalt, C.R. Bolognesi, and S.P. Watkins, 鈥淥ptical and electrical characterization of OMVPE-grown AlGaAsSb epitaxial layers on InP substrates鈥, J. Cryst. Growth, 287, 532, (2006)
C.R. Bolognesi, H.G. Liu, N. Tao, X. Zhang, S. Bagheri-Najmi, and S.P. Watkins, 鈥淣eutral base recombination in InP/GaAsSb/InP double-heterostructure bipolar transistors: Suppression of Auger recombination in p+ GaAsSb base layers鈥, Appl. Phys. Lett. 86, 253506 (2005).
W.Y. Jiang, J.Q. Liu, M.G. So, K. Myrtle, K.L. Kavanagh, S.P. Watkins, 鈥淪urface modifications induced by bismuth on (001) GaAs surfaces鈥 J. Cryst. Growth, 277, 85, (2005)
L. Zheng, Z. Zhang, Y. Zeng, S.R. Tatavarti, S.P. Watkins, C.R. Bolognesi, S. Demiguel, J.C. Campbell, 鈥淒emonstration of high-speed staggered lineup GaAsSb/InP Uni-traveling carrier photodiodes鈥, IEEE Photonics Technology Letters, 17, 651, (2005).
H. G. Liu, N. Tao, S. P. Watkins, and C. R. Bolognesi, 鈥淓xtraction of the Average Collector Velocity in High-Speed 鈥淭ype-II鈥 InP鈥揋aAsSb鈥揑nP DHBTs鈥, IEEE Electron Dev. Lett. 25, 769 (2004)
W. Jiang, J. Q. Liu, M.G. So, T. S. Rao, K.L. Kavanagh, and S.P. Watkins, 鈥淓ffect of Bi surfactant on atomic ordering of GaAsSb鈥, Appl. Phys. Lett., 85, 5589 (2004).
Z.Q. Li, V. Zhou, S. Li, T.S. Rao, W.Y. Jiang, S.P. Watkins, 鈥淐hemical kinetics and design of gas inlets for III-V growth by MOVPE in a quartz showerhead reactor鈥 accepted in J. Cryst. Growth, 272, 47 (2004).
O.J. Pitts, S.P. Watkins, C. X. Wang, J. A. H. Stotz, T. A. Meyer, M. L. W. Thewalt 鈥淯ltrathin type-II GaSb/GaAs quantum wells grown by OMVPE鈥, J. Cryst. Growth, 269, 187, (2004).
S. Lam, C.R. Bolognesi, and S.P. Watkins, "Characterization of InP electron-initiated impact ionization in low electric fields using abrupt junction NpN InP/GaAsSb/InP double heterojuntion bipolar transistors", Appl. Phys. Lett., 83, 5548 (2003).
C.R. Bolognesi, M.W. Dvorak, S.P. Watkins, 鈥淭ype II Base-Collector Performance Advantages and Limitations in High-Speed NPN double heterojunction bipolar transistors (DHBTs)鈥 IEICE Trans. Electron. E85-C, 1929 (2003)
O.J. Pitts, S.P. Watkins, C.X. Wang, V. Fink, and K.L. Kavanagh, "Antimony segregation in GaAs-based multiple quantum well structures" J. Cryst. Growth, 254, 28, (2003)
R.D. Wiersma, J.A.H. Stotz, O.J. Pitts, C.X. Wang, M.L.W. Thewalt, and S.P. Watkins, "Electrical and optical properties of carbon doped GaSb", Phys. Rev. B67, 165202 (2003)
S.P. Watkins, R.D.Wiersma, C.X. Wang, O.J. Pitts, and C.R. Bolognesi, "Structural effects of carbon in GaSb grown by metalorganic vapor phase epitaxy", J. Cryst. Growth, 248, 274 (2003).
C.X. Wang, O.J. Pitts, and S.P. Watkins, "Time-resolved reflectance difference spectroscopy study of Sb- and As- terminated InP(100) surfaces", J. Cryst. Growth, 248, 259 (2003).
O.J. Pitts, S.P. Watkins, and C.X. Wang, "RDS characterization of GaAsSb and GaSb grown by MOVPE", J. Cryst. Growth, 248, 249 (2003).
X.K. Chen, R. Wiersma, C.X. Wang, O.J. Pitts, C. Dale, C.R. Bolognesi, S.P. Watkins, "Local vibrational modes of carbon in GaSb and GaAsSb", Appl. Phys. Lett. 80, 1942 (2002).
C.R. Bolognesi, M.W. Dvorak, N. Matine, O.J. Pitts, S.P. Watkins, "Ultrahigh performance staggered lineup ("Type-II") InP/GaAsSb/InP NpN double heterojunction bipolar transistors", Jpn. J. Appl. Phys. 41,1131 (2002).
C.R. Bolognesi, N.Matine, M.W. Dvorak, P. Yeo, X.G. Xu, and S.P Watkins, "InP/GaAsSb/InP double HBTs: a new alternative for InP-based DHBTs", IEEE Trans. Electron Dev., 48, 2631 (2001).
R. Wiersma, J.A.H. Stotz, O.J. Pitts, C.X. Wang, M.L.W. Thewalt, and S.P. Watkins, "P-type carbon doping of GaSb", J. Electron. Materials, 30, 1429 (2001).
O.J. Pitts, S.P. Watkins, C.X. Wang, J.A.H. Stotz, and M.L.W. Thewalt, "in situ monitoring, structural and optical properties of ultrathin GaSb/GaAs quantum wells, grown by OMVPE", J. Electron. Materials, 30, 1412 (2001).
V. Fink, E. Chevalier, O.J. Pitts, M.W. Dvorak, K.L. Kavanagh, C.R. Bolognesi, S.P. Watkins, S. Hummel, N. Moll, "Anisotropic resistivity correlated with atomic ordering in p-type GaAsSb", Appl. Phys. Lett., 79, 2384 (2001).
M.W. Dvorak, C.R. Bolognesi, O.J. Pitts, S.P. Watkins, "300 GHz InP/GaAsSb/InP double HBTs with high current capability and BVCEO 鲁6V", IEEE Electron Device Lett., 22, 361 (2001).
M. W. Dvorak, N. Matine, C. R. Bolognesi, X. G. Xu and S. P. Watkins, "Design and performance of InP/GaAsSb/InP double heterojunction bipolar transistors", J. Vac. Sci. Technol. A 18, 761 (2000).
S.P. Watkins, T. Pinnington, J. Hu, P. Yeo, M. Kluth. N.J. Mason, R.J. Nicholas and P.J. Walker, "Infrared single wavelength gas composition monitoring for metalorganic vapour phase epitaxy", J. Cryst. Growth, 221, 166 (2000).
S.P. Watkins, O. Pitts, C. Dale, X.G.Xu, M. Dvorak, N. Matine, and C.R. Bolognesi, "Heavily carbon-doped GaAsSb grown on InP for HBT applications", J. Cryst. Growth, 221, 59 (2000).
R. Beaudry, X.G. Xu, and S.P. Watkins, "Photoreflectance study of phosphorous passivation of GaAs" J. Appl. Phys. 87, 7838 (2000).
C. R. Bolognesi and S. P. Watkins, "InP-Based Double Heterojunction Bipolar Transistors: It May Not Have to be GaInAs", Compound Semiconductor 6, 94 (2000).
J.A. Gupta, S.P. Watkins, E.D. Crozier, J.C. Woicik, D.A. Harrison, D. Jiang, I.J. Pickering, and B.A Karlin, "Layer perfection in ultrathin InAs quantum wells in GaAs (001)", Phys. Rev. B61, 2073(2000).