Optoelectronics Laboratory

This laboratory is located in rooms 146 & 148 in the Natural Science Center (NSC) Building. We carry out research in infrared applications for safe and healthy living: Cancer and Colitis screening (Biomedical Physics) and semiconductor optoelectronics devices (Infrared Physics) and under the direction of Prof. A. G. U. Perera.

The work reported here is supported either by the U.S. National Science Foundation (NSF),  National Aeronautics and Space Administration (NASA), U.S. Army and / or Georgia State University. However the authors (listed under different research topics) are responsible for the ideas expressed in the publications.

Biomedical Physics: In this project we are trying to understand the interaction of infrared radiations with the soft diagnostic mediums, mainly the serum samples. The interaction of light is used to evaluate disease (Inflammatory bowel diseases (IBD) and cancers) associated changes. Our, study covers infrared spectral imaging, spectral analysis and perform statistical measures. To establish an association with the disease associated changes in the tissue samples, we also perform white light microscopic imaging and image analysis.

Infrared Physics: In this project, our focus is on device concepts, device physics, theory, modeling and the experimental measurements, which involve either interfacial or intra band (rather than inter band) electronic process.

Members of the group

The main areas of interest are:

• Minimally invasive disease diagnostics

· Collaborators:

§ Dr. D. Merlin

§ Dr. R. Aneja

§ Dr. G. Qin

§ Dr. M. Dayananda

§ Dr. V. Jayaweeera

§ Dr. Y. Liu

§ Dr. J. Hillard

· Publications:

§ “Optimizing infrared spectral discrimination to enhance disease diagnostics: monitoring the signatures of inflammatory bowel diseases with anti-TNFα therapy”, H. Ghimire, X. Hu, G. Qin and A. G. Unil Perera, Biomedical Optics Express (2020) 11(8), 4679-4694. (Full paper in PDF format)

§ “ Protein Conformational Changes in Breast Cancer Sera Using Infrared Spectroscopy Analysis”, H. Ghimire, C. Garlapati, E. A. M. Janssen, U. Krishnamurti, G. Qin, R. Aneja and A. G. Unil Perera, cancers (2020) (doi:10.3390/cancers12071708). (Full paper in PDF format)

§ “ Longitudnal analysis of molecular alteration in serum samples of dextran sodium sulfate-induced colitis mice by using infrared spectroscopy”, H. Ghimire, P. V. Jayaweera, A. G .U. Perera, Infrared Phys. & Technol., 1;97, 33–37, 2019. (Full paper in PDF format)

§ “ATR-FTIR spectral discrimination between normal and tumorous mouse models of lymphoma and melanoma from serum samples”, H. Ghimire, M. Venkataramani, Z. Bian, Y. Liu, and A. G. U. Perera, Scientific Reports 7, Article number: 16993 (2017). (Full paper in PDF format)

§ “Protein secondary structure analysis of dried blood serum using infrared spectroscopy to identify markers for colitis screening”, J. Titus, H. Ghimire, E. Viennois, D. Merlin, A. G. U. Perera, Published online: 25 July 2017. (DOI:10.1002/jbio.201700057) (Full paper in PDF format)

§ “Minimally invasive screening for colitis using attenuated total internal reflectance fourier transform infrared spectroscopy”, Titus J., Viennois E Merlin D., Unil Perera A.G., J. Biophotonics 10, 465–472 (2017). (Full paper in PDF format)

§ “Early detection of cell activation events by means of attenuated total reflection Fourier transform infrared spectroscopy”, Jitto Titus, Chadi Filfili, Julia K Hilliard, John A Ward and A. G. U. Perera, Appl. Phys. Lett. 104, 243705 (2014). (Full paper in PDF format)

• Semiconductor Infrared Devices

· Split-off Band Infrared detectors

§ Photovoltaic Infrared Detection with p-type Graded Barrier Heterostructures, (P.K.D.D.P. Pitigala, S. G. Matsik, A. G. U. Perera , S. P. Khanna, L. H. Li, E. H. Linfield, Z. R. Wasilewski, M. Buchanan, and H. C Liu) Journal of Applied. Physics 111, 084505 (2012) .(Full paper in PDF format)

§ Dielectric function model for p-type semiconductor inter-valence band transitions, (Yan-Feng Lao and A. G. Unil Perera) Journal of Applied Physics 109, 103528 (2011) .(Full paper in PDF format)

§ Effects of Graded Barriers on the Operation of Split-Off Band Infrared Detectors, (A. G. U. Perera, S. G. Matsik, D.P. Pitigala, Y.F Lao, S. Khanna, L.H.Li, E.Linfield, Z.R.Wasilewski, M.Buchanan, X.H.Wu, and H.C.Liu.) Infrared Phys. Technol. 296-301 (2011)54, 296-301 (2011) .(Full paper in PDF format)

§ Highly sensitive GaAs/AlGaAs heterojunction bolometer, (P.K.D.D.P. Pitigala, P.V.V.Jayaweera, S.G.Matsik, A.G.U.Perera and H.C.Liu) Sensors and Actuators A 167, 245-248 (2011) .(Full paper in PDF format)

§ Light-hole and heavy-hole transitions for high-temperature long-wavelength infrared detection, (Y.F. Lao, P.K.D.D.P. Pitigala, A.G.U. Perera, H.C. Liu, M.Buchanan, Z.R. Wasilewski, K.K. Choi,and P. Wijewarnasuriya) Appl. Phys. Lett. 97, 091104 (2010).(Full paper in PDF format)

§ Analysis of Dark Current Mechanisms for Split-Off Band Infrared Detectors at High Temperatures , (Y. F. Lao, P. V. V. Jayaweera, Steven G. Matsik, A. G. Unil Perera, H. C. Liu, M. Buchanan, and Z. R. Wasilewski) IEEE Transactions on Electron Devices 57, 1230 (2010)..(Full paper in PDF format)

§ Operating temperature and the responsivity of split-off band detectors, (A. G. U. Perera, P. V. V. Jayaweera, S. G. Matsik, H. C. Liu, M. Buchanan, Z. R. Wasilewski) Infrared Physics & Technology 52, 241-246 (2009)..(Full paper in PDF format)

§ Device modeling for split-off band detectors, (S. G. Matsik, P. V. V. Jayaweera, A. G. U. Perera, K. K. Choi, and P. Wijewarnasuriya) Journal of Applied Physics 106, 1064503 (2009)..(Full paper in PDF format)

§ Uncooled infrared detectors for 3-5 µm and beyond, (P.V.V.   Jayaweera, S.G. Matsik, A.G.U. Perera, H.C. Liu, M. Buchanan, and Z. R. Wasilewski ) Appl. Phys. Lett. 93, 021105 (2008).(Full paper in PDF format)

§ Spin split-off transition based IR detectors operating at high temperatures (P.V.V. Jayaweera, S.G. Matsik, K. Tennakone, A.G.U. Perera, H.C. Liu and S. Krishna ) Infrared Physics & Technology, 50, 279-283 (2007) (Full paper in PDF format)

§ High Operating Temperature Split-off Band Infrared Detectors (A. G. U. Perera, S. G. Matsik, P. V. V. Jayaweera, K. Tennakone, H. C. Liu, M. Buchanan G. Von Winckel, A. Stintz, and S. Krishna) Appl.Phys.Lett., 89, 131118, (2006) (Full paper in PDF format)

• Heterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) IR detectors
  
• n-type GaAs/AlGaAs Heterostructure detector with a 3.2 threshold frequency (A. B. Weerasekara, M. B. M. Rinzan, S. G. Matsik, A. G. U. Perera, M. Buchanan, H. C. Liu, G. von Winckel, A. Stintz, and S. Krishna) Optics Letters, 32 (10), 1335-1337, (2007) (Full paper in PDF format).
• Effects of a p–n junction on heterojunction far infrared detectors（S.G. Matsik, M.B.M. Rinzan, A.G.U. Perera, H.H. Tan, C. Jagadish and H.C. Liu）Infrared Physics & Technology, 50, 274-278 (2007) (Full paper in PDF format)
• Quantum mechanical effects in internal photoemission THz detectors (M.B. Rinzan, S. Matsik and A.G.U. Perera) Infrared Physics & Technology, 50,199-205 (2007) (Full paper in PDF format)
• Si doped GaAs/AlGaAs terahertz detector and phonon effect on the responsivity (A.B. Weerasekara, M.B.M. Rinzan, S.G. Matsik, A.G.U. Perera, M. Buchanan, H.C. Liu, G. von Winckel, A. Stintz and S. Krishna) Infrared Physics & Technology, 50,194-198 (2007) (Full paper in PDF format)
• Terahertz absorption in AlGaAs films and detection using heterojunctions (M. B. M. Rinzan,  A. G. U. Perera, S. G. Matsik, H. C. Liu, M. Buchanan, G. Von Winckel, A. Stintz, and S. Krishna) Infrared Physics & Technology., 47, 188–194, (2005) (Full paper in PDF format) 
• AlGaAs emitter/GaAs barrier Terahertz detector with a 2.3 THz threshold (M.B.M. Rinzan, A. G. U. Perera, S. G. Matsik, H. C. Liu, Z. Wasilewski and M. Buchanan)  Appl. Phys. Lett, 86,  071112, (2005). (Full paper in PDF format)
• Effect of Doped Substrate on GaAs/AlGaAs Interfacial Workfunction IR Detector Response through Cavity Effect (S. G. Matsik, M. B. M. Rinzan, D. G. Esaev, A. G. U. Perera, G. Von Winckel, A. Stintz, and S. Krishna) IEEE Transactions on Electron Devices, 52 (3), 413-418, (2005). (Full paper in PDF format)
• 20  micron cutoff heterojunction interfacial workfunction internal photoemission detectors, ( S. G. Matsik, M. B. M. Rinzan, A. G. U. Perera, H. C. Liu and M. Buchanan)  Applied Physics letters, 84, 3435-3437, (2004). (Full paper in PDF format)
• Free Carrier Absorption in Be-doped Epitaxial AlGaAs Thin Films (M. B. M. Rinzan, D. G. Esaev, A. G. U. Perera, S. G. Matsik, G. Von Winckel, A. Stintz, and S. Krishna) Applied Physics Letter, 85 (22),  5236-5238, (2004). (Full paper in PDF format)
• Design and Optimization of GaAs/AlGaAs Heterojunction Infrared Detectors.  (D. G. Esaev, M. B. M. Rinzan, S. G. Matsik, and A. G. U. Perera) Journal of Applied Physics,  96, 4588-4597, (2004). (Full paper in PDF format)
• Resonant cavity enhancement in heterojunction GaAs/AlGaAs terahertz detectors, (D. G. Esaev, S. G. Matsik, M. B. M. Rinzan, A. G. U. Perera and H. C. Liu) Journal of Applied Physics, 93, 1879 - 1883 (2003). (Full paper in PDF format)
• Cutoff tailorability of heterojunction terahertz detectors, ( S. G. Matsik, M. B. M. Rinzan, A. G. U. Perera, H. C. Liu, Z. R. Wasilewski, and M. Buchanan) Appl. Phys. Lett. 82, 139 (2003). (Full paper in PDF format)
• Heterojunction Wavelength-Tailorable Far-Infrared Photodetectors with Response out to 70 Microns Appl. Phys. Lett.,  78, 2241~2243, (2001). (Full paper in PDF format)

o Multi and Dual Band Infrared detectors

§ Bias-selectable Five Band Bias-Selectable Integrated Quantum Well Detector in an n-p-n Architecture (G. Ariyawansa, Y. Aytac, A. G. U. Perera, S. G. Matsik, M. Buchanan, Z. R. Wasilewski, and H. C. Liu), Appl. Phys. Lett.97, 231102 (2010). (Full paper in PDF format)

§ Bias-selectable Quantum dot nanostructures for multi-band infrared detection (A. G. U. Perera, G. Ariyawansa, G. Huang, P. Bhattacharya), Infrared Physics & Technology 52, 252-256 (2009). (Full paper in PDF format)

§ Bias-selectable tri-color tunneling quantum dot infrared photodetector for atmospheric windows (G. Ariyawansa, V. Apalkov, A. G. U. Perera, S. G. Matsik, G. Huang, and P. Bhattacharya), Appl. Phys. Lett.92, 111104 (2008). (Full paper in PDF format)

§ A Multi-Color Quantum Dot Intersublevel Detector with Photoresponse in the Terahertz Range (G. Huang, J. Yang and P. Bhattacharya, G. Ariyawansa and A. G. U. Perera), Appl. Phys. Lett. 92, 011117, (2008). (Full paper in PDF format)

§ Dual-band pixelless upconversion imaging devices, (L. K. Wu, H. L. Hao, W. Z. Shen, G. Aeiyawansa, A. G. U. Perera, and S. G. Matsik), Optics Letters, 32 2366-2368, (2007) (Full paper in PDF format)

§ Wavelength and Polarization Selective Multi-Band Tunneling Quantum Dot Detectors, (A. G. U. Perera, G. Ariyawansa, V. M. Apalkov, S. G. Matsik, X. H. Su, S. Chakrabarti, and P. Bhattacharya), Opto-Electron. Rev., 15(4), 223–228 (2007).(Full paper in PDF format)

§ Performance improvements of ultraviolet/infrared dual-band detectors (A.G.U. Perera, G. Ariyawansa, M.B.M. Rinzan, M. Stevens, M. Alevli, N. Dietz, S.G. Matsik, A. Asghar, I.T. Ferguson, H. Luo et al.) Infrared Physics & Technology, 50, 142-148 (2007) (Full paper in PDF format)

§ Quantum structures for multiband photon detection (A.G.U. Perera) Opto-Electronics Review, 14 (2), 103-112, (2006) (Full paper in PDF format)

§ GaN/AlGaN heterojunction infrared detector responding in 8-14 µm and 20-70 µm ranges (G. Ariyawansa, M. B. M. Rinzan, M. Strassburg, N. Dietz , A. G. U. Perera, S. G. Matsik, A. Asghar, I. T. Ferguson, H. Luo, and H. C. Liu)  Appl.Phys.Lett., 89, 141122 (2006) (Full paper in PDF format)

§ GaN/AlGaN ultraviolet/infrared dual-band detector (G. Ariyawansa, M. B. M. Rinzan, M. Alevli, M. Strassburg, N. Dietz , A. G. U. Perera, S. G. Matsik, A. Asghar, I. T. Ferguson, H. Luo, A. Bezinger, and H. C. Liu)  Appl.Phys.Lett., 89, 091113, (2006) (Full paper in PDF format)

§ Characteristics of a Si dual-band detector responding in both near- and far-infrared regions (G. Ariyawansa, M. B. M. Rinzan, S. G. Matsik, A. G. U. Perera, G. Hastings, H. C. Liu, M. Buchanan, G. I. Sproule, V. I. Gavrilenko, and V. P. Kuznetsov) Appl.Phys.Lett., 89, 061112, (2006) (Full paper in PDF format)

· Uncooled Infrared detectors

· Uncooled infrared detectors for 3-5 µm and beyond, (P.V.V.   Jayaweera, S.G. Matsik, A.G.U. Perera, H.C. Liu, M. Buchanan, and Z. R. Wasilewski ) Appl. Phys. Lett. 93, 021105 (2008).(Full paper in PDF format)

· Displacement currents in semiconductor quantum dots embedded dielectric media: A method for room temperature photon detection, (P. V. V. Jayaweera, A. G. U. Perera, and K. Tennakone) Applied Physics Letters 91, 063114-3, (2007).(Full paper in PDF format)

· Dye-sensitized Near-infrared Room-temperature Photovoltaic Photon Detectors (P.V.V. Jayaweera, A.G.U. Perera, M.K.I. Senevirathna, P.K.D.D.P. Pitigala, and K. Tennakone) Applied Physics Letter, 85 (23), 5754-5756, (2004). (Full paper in PDF format)

· Construction of a Photovoltaic Device by Deposition of Thin Films of the Conducting Polymer Polythiocyanogen, (V.P.S. Perera,  P.V.V.  Jayaweera,  P.K.D.D.P.  Pitigala,  P.K.M. Bandaranayake,  G. Hastings,  A. G. U. Perera,  K. Tennakone) Synthetic Metals, 143, 283-287, (2004). (Full paper in PDF format)

o Quantum-dot Infrared detectors

(i) Self-Assembled Quantum Dots

§ Bias-selectable tri-color tunneling quantum dot infrared photodetector for atmospheric windows (G. Ariyawansa, V. Apalkov, A. G. U. Perera, S. G. Matsik, G. Huang, and P. Bhattacharya), Appl. Phys. Lett.92, 111104 (2008). (Full paper in PDF format)

§ A Multi-Color Quantum Dot Intersublevel Detector with Photoresponse in the Terahertz Range (G. Huang, J. Yang and P. Bhattacharya, G. Ariyawansa and A. G. U. Perera), Appl. Phys. Lett. 92, 011117, (2008). (Full paper in PDF format)

§ High-Temperature Tunneling Quantum-Dot Intersublevel Detectors for Mid-Infrared to Terahertz Frequencies (P. Bhattacharya, Xiaohua Su, G. Ariyawansa, A. G. U. Perera), Proceedings of the IEEE 95, 1828– 1837 (2007). (Full paper in PDF format)

• Multi-color tunneling quantum dot infrared photodetectors operating at room temperature (G. Ariyawansa, A.G.U. Perera, X.H. Su, S. Chakrabarti and P. Bhattacharya) Infrared Physics & Technology, 50,156-161 (2007) (Full paper in PDF format)
• Terabertz detection with tunneling quamtum dot intersublevel photodetetor (X.H. Su, J. Yang, P. Bhattacharya, G. Ariyawansa, and A.G. U. Perera) Appl.Phys.Lett., 89, 031117 (2006) (Full paper in PDF format)
• High Performance mid-infrared quantum dot infrared photodetectors (S. Chakrabarti, A D Stiff-Roberts, X Su, P Bhattacharya, G Ariyawansa, and A. G. U. Perera) J. Phys D. Appl. Phys. 38, 2135-2141, (2005).  (Full paper in PDF format)
• Characteristics of a Tunneling Quantum-dot Infrared Photodetector Operating at Room Temperature (P. Bhattacharya, X. H. Su,  S. Chakrabarti,  G. Ariyawansa,  and  A. G. U. Perera), Appl. Phys. Lett, 86, 191106, (2005). (Full paper in PDF format)
• Characteristics of a Multicolor InGaAS--GaAs Quantum-Dot Infrared Photodetector (S.Chakrabarti, Member, IEEE, X. H. Su, P. Bhattacharya, Fellow, IEEE, G. Ariyawansa, and A.G.U. Perera) IEEE Photonics Technology Letters , 17 (1), 178-180, (2005). (Full paper in PDF format)
• Effect of Well Width on Three Color Quantum Dot-in-a-Well Infrared Detectors (G. Ariyawansa, A. G. U. Perera, Senior Member, IEEE, G. S. Raghavan, G. von Winckel, A. Stintz, and Sanjay Krishna), IEEE Photonics Tech. Letts, 17, 1064-1066, (2005). (Full paper in PDF format)
• Three-color (p1~3.8  µm, p2~8.5  µm, and p3~23.2  µm) InAs/InGaAs quantum-dots-in-a-well detector, (G. Ariyawansa, S. G. Matsik, A. G. U. Perera, S. Krishna, S. Raghavan, G. von Winckel, and A. Stintz) Applied Physics Letters,  83, 2745-2747 (2003). (Full paper in PDF format)

(ii) Collidol Quantum Dots

§ Displacement currents in semiconductor quantum dots embedded dielectric media: A method for room temperature photon detection, (P. V. V. Jayaweera, A. G. U. Perera, and K. Tennakone) Applied Physics Letters 91, 063114-3, (2007).(Full paper in PDF format)

• Homojunction Interfacial Workfunction Internal Photoemission (HIWIP) IR detectors

• GaSb homojunctions for Far-IR (THz) Detection (P. V. V. Jayaweera, S. G. Matsik, and A. G. U. Perera, Y. Paltiel, Ariel Sher and Arie Raizman, H. Luo, and H. C. Liu), Applied Physics Letters, 90, 111109, (2007) (Full paper in PDF format)
• Near- and Far-Infrared p-GaAs Dual Band Detector (G. Ariyawansa, M.B.M. Rinzan, D. G. Esaev, S. G. Matsik, G. Hastings, A. G. U. Perera, H. C. Liu, B. N. Zvonkov, and V. I. Gavrilenko), Appl. Phys. Lett, 86, 143510, (2005). (Full paper in PDF format)
• High performance single emitter homojunction interfacial workfunction far infrared detectors, (D. G. Esaev, M. B. M.  Rinzan, S. G. Matsik, A. G. U. Perera, H. C. Liu, B. N. Zvonkov , V. I. Gavrilenko and A. A. Belyanin)  Journal of Applied Physics,   95, 512-519, (2004) (Full paper in PDF format)
• The effects of light–heavy hole transitions on the cutoff wavelengths of far infrared detectors, (A. G. U. Perera, S. G. Matsik, M. B. M. Rinzan, A. Weerasekara, M. Alevli, H. C. Liu, M. Buchanan, B. Zvonkov and V. Gavrilenko) Infrared Physics & Technology, 44(5-6), 347-353, (2003). (Full paper in PDF format)
• Optical Cavity Architecture Solid-State Electronics, 45, 87-93, (2001). (Full paper in PDF format)
• Effect of interface states on the performance of GaAs p⁺ -i far-infrared detectors J. Vac. Sci Technology A 18: (2) 597-600, (2000). (Full paper in PDF format)
• Negative capacitance of GaAs homojunction far-infrared detectors Appl. Phys. Lett, 74, 21. (Full paper in PDF format)
• Classification and Analysis J. Appl. Phys.,  77(2) (Full paper in PDF format)
• Dark Current Issues Appl. Phys. Lett.,  66(17). (Full paper in PDF format)
• Space Charge Effects Solid-State Electronics,  39(5). (Full paper in PDF format)
• GaAs HIWIP Structures J. Appl. Phys.,  81(7). (Full paper in PDF format)
• FIR Absorption in Si Appl. Phys. let,  71(4). (Full paper in PDF format) 
• Bias Effects in High performance GaAs... Appl. Phys. let,  71(18). (Full paper in PDF format)
• Si Detector Performance IEEE Trans. Elect. Devices,  44(12)
• Photocnductive Generation and Gain J. Appl. Phys.,  83(7). (Full paper in PDF format)
• Demonstration of Si homojunction Appl. Phys. Lett.,  72(18). (Full paper in PDF format)
• Effect of Emitter parameters IEEE Trans. Elect. Devices,  45(8). (Full paper in PDF format)
• Photoconductivity in homojunction ... Infrared Physics & Technology,  237. (Full paper in PDF format)
• A review on Homojunction structures Physics of Thin Films,  21

o Dye Sensitized Semiconductor Nanostructure

• Sensitization of TiO2 and ZnO nanocrystalline films with acriflavine, (M.K.I. Senevirathne, P.K.D.D.P. Pitigala, V. Sivakumar,    P.V.V. Jayaweera, A.G.U. Perera and K. Tennakone), Journal of Photochemistry and Photobiology A: Chemistry, 195, 364-367,(2008). (Full paper in PDF format)
• Why Gratzel^′s cell works so well (P.V.V. Jayaweera, A.G.U. Perera and K. Tennakone) Inorganica Chimica Acta, 361(3), 707-711, February (2008),  (Full paper in PDF format)
• 1/f Noise in dye-sensitized solar cells and NIR photon detectors(P.V.V. Jayaweera, P.K.D.D.P. Pitigala, M.K.I. Seneviratne, A.G.U. Perera and K. Tennakone) Infrared Physics & Technology, 50, 270-273 (2007) (Full paper in PDF format)
• 1/f noise and dye-sensitized solar cells (P. V. V. Jayaweera, P. K. D. D. P. Pitigala, A. G. U. Perera and K. Tennakone) Semicond. Sci. Technol. 20, L40–L42, (2005).  (Full paper in PDF format)
• Dye-sensitized Near-infrared Room-temperature Photovoltaic Photon Detectors (P.V.V. Jayaweera, A.G.U. Perera, M.K.I. Senevirathna, P.K.D.D.P. Pitigala, and K. Tennakone) Applied Physics Letter, 85 (23), 5754-5756, (2004). (Full paper in PDF format)
• Construction of a Photovoltaic Device by Deposition of Thin Films of the Conducting Polymer Polythiocyanogen, (V.P.S. Perera,  P.V.V.  Jayaweera,  P.K.D.D.P.  Pitigala,  P.K.M. Bandaranayake,  G. Hastings,  A. G. U. Perera,  K. Tennakone) Synthetic Metals, 143, 283-287, (2004). (Full paper in PDF format)
  
  
• Semiconductor Materials Properties
  

§ Optical properties of n-doped Ga1−xMnxN epitaxial layers grown by metal-organic chemical-vapor in mid and far "5-50 _m… IR range, (A. B. Weerasekara, Z. G. Hu, N. Dietz,  A. G. U. Perera, A. Asghar,  M. H. Kane, M. Strassburg and I. T. Ferguson), J. Vac. Sci. Technol. B 26(1) 52-55 Jan/Feb (2008). (Full paper in PDF format)

§ Carrier concentration and surface electron accumulation in indium nitride layers grown by high pressure chemical vapor deposition (R. P. Bhatta, B. D. Thomas, A. Weerasekera, A. G. U. Perera, M. Alevli, and N. Dietz) J. Vac. Sci. Technol. A 25(4) 967-970 July (2007) (Full paper in PDF format)

§ Infrared optical anisotropy of diluted magnetic Ga_1-x Mn_xN/c –sapphire epilayers with a GaN buffer layer by metaloorganic chemical vapor deposition. (Z. G. Hu, A. B. Weerasekara, N. Dietz A. G. U. Perera, M. Strassburg, M. H. Kane, A. Asghar and I. T. Ferguson) PRB. 75, 205320 (2007)  (Full paper in PDF format)

• Optical Studies of MOCVD grown GaN based ferromagnetic semiconductorepilayers and devices (M. H. Kane, M. Strassburg, W. E. Fenwick, A. Asghar, J. Senawiratne, D. Azamat, Z. Hu, E. Malguth, S. Graham, U. Perera, W. Gehlhoff, A. Hoffmann, N. Dietz, C. J. Summers, I. T. Ferguson) Physica Status solidi, 3 (6), 2237-2240 ( 2006) (Full paper in PDF format)
• The Characterization of InN layers grown by high-pressure chemical vapor deposition (M. Alevli, G. Durkaya, W. Fenwick, A. Weerasekara, V. Woods, I. Ferguson, U. Perera and N. Dietz) Appl.Phys.Lett., Lett. 89, 112119, (2006) (Full paper in PDF format) 
• Longitudinal–optical phonon hole plasmon coupled modes in heavily doped p-type GaSb:Zn epitaxial  films (Z. G. Hu, M. B. M. Rinzan, A. G. U. Perera, M. Zhu, Y. Paltiel, A. Raizman, and A. Sher)  Eur. Phys. J. B., 50, 403-410, (2006) (Full paper in PDF format)
• Lattice vibrations in hexagonal Ga1–xMnxN epitaxial films on c-plane sapphire substrates by infrared reflectance spectra (Z. G. Hu, M. Strassburg, A. Weerasekara, N. Dietz, A. G. U. Perera, M. H. Kane, A. Asghar, and I. T. Ferguson)  Appl. Phys. Lett., 88, 061914, (2006) (Full paper in PDF format)  
• Composition dependence of the infrared dielectric function in Si- doped hexagonal AlxGa1-xN films on c-plane sapphire substrates (Z. G. Hu, M.Strassburg, N. Dietz. A.G. U. Perera, A. Asghar, I.T. Ferguson) Phys. Rev. B., 72, 245326, (2005) (Full paper in PDF format)
• Zn-Doped GaSb Epitaxial Film Absorption Coefficients at Terahertz Frequencies and Detector Applications (Z. G. Hu, A. G. U. Perera, Y. Paltiel, A. Raizman, & A. Sher), Journal of Applied Physics, 98, 023511, (2005). (Full paper in PDF format)
• Optical Characterizations of Heavily Doped p-type AlxGa1-xAs and GaAs Epitaxial Films at Terahertz Frequencies (Z. G. Hu, M. B. M. Rinzan, S. G. Matsik, A. G. U. Perera, G. Von Winckel, A. Stintz, and S. Krishna), Journal of Applied Physics, 97, 093529, (2005). (Full paper in PDF format)
• Free Carrier Absorption in Be-doped Epitaxial AlGaAs Thin Films (M. B. M. Rinzan, D. G. Esaev, A. G. U. Perera, S. G. Matsik, G. Von Winckel, A. Stintz, and S. Krishna) Applied Physics Letter, 85 (22),  5236-5238, (2004). (Full paper in PDF format)
• FIR Absorption In p-GaAs Hiwip Detectors Structures with thick Intrinsic Layers Proceedings of the Academy of Sciences, 66(2.c). 254-256, (2002). (Full paper in PDF format)
• Be- and C-doped GaAs Epilayers and Far Infrared Detector Applications J. Appl. Phy., 89(6), 3296-3300, (2001). (Full paper in PDF format)
• FIR Absorption in GaAs Infrared Physics & Technology,  38, 133-138, (1997). (Full paper in PDF format) 

o Physics and IR Applications of Multi-Quantum Well Structures

• Transient Photocurrent Overshoot in Quantum-well Infrared Photodetectors, Applied Physics Letters, 79(13), 2094-2096, (2001). (Full paper in PDF format)
• Spontaneous Oscillations and Triggered Pulsing in MQW Structures Solid State Electronics, 45, 1121-1125, (2001). (Full paper in PDF format )
• Transient Photocurrent Overshoot in Quantum Well Infrared Photodetectors Infrared Physics & Technology, 42, 243-247, (2001). (Full paper in PDF format)
• Space Charge Spectroscopy of Integrated QWIP-LED Infrared Physics & Technology, 42, 259-265, (2001).(Full paper in PDF format) 
• 35 micron GaAs/InGaAs QWIPS Appl. Phys. Lett. 77, 741~743, (2000). (Full paper in PDF format)
• 35 µm cutoff bound-to-quasibound and bound-to-continuum InGaAs QWIPs Infrared Physics & Technology, 42, 157-162, (2001). (Full paper in PDF format)
• Effects of traps on the dark current transient in GaAs/AlGaAs quantum well infrared photodetectors Physica E. 7(1-2), 130~134, (2000). (Full paper in PDF format)
• Quasi Bound Barrier Resonances
• 28 micron GaAs/AlGaAs QWIPS Appl. Phys. Lett., 72(13). (Full paper in PDF format)
• Vertical Charge Transport in MQWs J. Appl. Phys, .83(2). (Full paper in PDF format)
• Pulsing in MQW Structures Appl. Phys. Lett.,  67(7). (Full paper in PDF format)
• Pulsing MQW IR detectors SPIE proceedings, 2746

• Infrared Emission
  
  
• LWIR Emission NATO ASI Series,  270
• Tunneling Times J. Appl. Phys., 79(10). (Full paper in PDF format)
• Quantum Well LWIR Emission - A Review Physics of Thin Films,  23
• Non-linear dynamics associated with semiconductor devices
  
  
• Bifurcation and Chaos in Pulsing Si p-i-n Structures Physica D,  84. (Full paper in PDF format) 
• Limit Cycles SPIE Proceedings,  2488
• Modelocking Appl. Phys. Lett., 51(14)
• Farey Fractions Physical Review Letters, 58(1)
• Semiconductor Neurons and Neural Network Emulations
  
  
• Grouping behavior of inter-pulse time intervals for triggered pulses in an AlGaAs/InGaAs multilayer structure (A. B. Weerasekara, S. G. Matsik, G. S. Cymbalyuk and A. G. U. Perera) Physica D, 215, 159-165, (2006). (Full paper in PDF format)
• Artificial Neurons using p-i-n Structures
• Transient Sensing using Retinal Concepts World Congress of Neural Networks, p. IV 704
• Bifurcation and Chaos in Pulsing Si Neurons
• Neural Nets and parallel ProcessorsSPIE Proceedings, 2488
• Quantum Well Neurons Appl. Phys. Lett.,  67(7) (Full paper in PDF format)

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