Peter Kozodoy - Academia.edu (original) (raw)

Papers by Peter Kozodoy

Light-Tracking Optical Device and Application to Light Concentration

Point-Of-Use Disinfection of Drinking Water using Cationic Antimicrobial Surface Coatings

Proceedings of the Water Environment Federation, 2009

Low-dimensional resonant tunnelling and Coulomb blockade: a comparison of fabricated versus impurity confinement

Semiconductor Science and Technology, 1994

... Rev. B 41 5459 [4] Tewordt M, Law V J, Kelly M J, Newbury R, Pepper ;vi, Peacock DC, Frost JE... more ... Rev. B 41 5459 [4] Tewordt M, Law V J, Kelly M J, Newbury R, Pepper ;vi, Peacock DC, Frost JEF, Ritchie D A and Jones GA C 1990 J. Phys.: Condens. ... B r71 Asahi H. Tewordt M. Svme R T. Kelly M J. Law V J. _ _ Frost J E F, Ritchik DA, Jones GA C and Pepper i4 i99i Surj Sci. ...

Magnesium-doped gallium nitride for electronic and optoelectronic device applications

Magnesium doping of gallium nitride (GaN) for p-type conductivity is a crucial technology for a h... more Magnesium doping of gallium nitride (GaN) for p-type conductivity is a crucial technology for a host of optoelectronic and electronic device applications. The performance of many of these devices is presently limited by the various difficulties associated with Mg doping, both fundamental (such as the deep nature of the Mg acceptor) and technological (such as the problems in forming ohmic contacts). Both types of issues are addressed in this work. Heavy doping effects have been investigated in order to understand the consequences of the high dopant concentration typically employed; increased compensation and a reduction in the acceptor binding energy are among the effects observed. The compensation level is believed to limit the hole mobility in these films, and is found to depend on the choice of growth conditions; the results point to nitrogen vacancies as a likely candidate for one of the compensating donor species. The optimization of various processing procedures has also been addressed. These include the annealing procedure used to remove the hydrogen passivation as well as ohmic contact recipes. In addition, the electrical effects of plasma-induced damage to the p-type GaN surface are investigated; these effects are particularly important for bipolar transistor applications where a plasma etch is needed in order to reveal the base layer. The electrical characteristics of GaN p-n junctions formed both with and without dislocations are compared using the lateral epitaxial overgrowth technique; the dislocations are found to be the dominant leakage path in reverse-bias operation. The electrical consequences of the deep Mg acceptor are also addressed. These include the unusual nature of the low-frequency depletion region, and dispersion in the high-frequency depletion region due to the finite response time of the Mg acceptor. Finally, a novel scheme is presented that uses the strong polarization fields present in AlGaN/GaN superlattices to enhance the doping efficiency of the Mg acceptor. The polarization fields lead to hole accumulation in parallel sheets, resulting in a spatially-averaged hole concentration that is temperature-stable and significantly enhanced from that obtained in bulk films.

Photonic device with segmented absorption design

Self-Tracking Concentrator for Photovoltaics

CLEO: 2015, 2015

Magnesium-doped gallium nitride for electronic and optoelectronic device applications

... Thanks also go out to Lorenzo Faraone and Jarek Antoszewski at the University of Western Aust... more ... Thanks also go out to Lorenzo Faraone and Jarek Antoszewski at the University of Western Australia for preliminary investigations in this area. A number of close friends have made my time as a grad student much more enjoyable. ...

A first look at AlGaN/GaN HBTs

Method for the growth of P-type gallium nitride and its alloys

InGaN/GaN field emitters with a piezoelectrically-lowered surface barrier

Eleventh International Vacuum Microelectronics Conference. IVMC'98 (Cat. No.98TH8382), 1998

ABSTRACT The operating characteristics of field emitters are exponentially dependent on two devic... more ABSTRACT The operating characteristics of field emitters are exponentially dependent on two device parameters: the field enhancement factor and the surface energy barrier height. In addition to these device parameters, the practical use of field emitters as electron sources is dependent on the stability and uniformity of field emission. We have investigated field emission from GaN field emitters because GaN has a high resistance to sputtering and is chemically inert. One drawback of GaN field emitters is that they are not easily sharpened. Thus, to lower the operating voltage of GaN-based field emitters we have investigated the lowering of the surface energy barrier using a strained-layer of InGaN on GaN field. The piezoelectric polarization produced in the strained InGaN forms a dipole much like the dipole formed by coating a surface with an electropositive adsorbate

52nd Electronic Components and Technology Conference 2002. (Cat. No.02CH37345), 2002

We are manufacturing widely tunable laser diodes with an integrated high-speed electro-absorption... more We are manufacturing widely tunable laser diodes with an integrated high-speed electro-absorption modulator for metro and all-optical switching applications. The monolithic integration of the device combines the functions of high power laser light generation (> lOmW), wavelength tuning over the entire C-band (>loochannels on 5OGHz grid), and high speed signal modulation (>2.5Gbit/s). The laser section of the chip contains two sampled grating DBRs with a gain and a phase section between them. Wavelength tuning is achieved by current injection into the waveguide layers of the DBRs. Since electronics tuning and not thermal or mechanical tuning is employed wavelength tuning can be easily performed on a short time scale of less than lOms which is required for various applications. Even 4011s tuning speed is feasible with the appropriate driver electronics. Transmission experiments show less than 1dB power penalty over 200km of standard single mode fiber for all channels.

AlGaN/GaN MODFETs with low ohmic contact resistances by source/drain n/sup +/ re-growth

Compound Semiconductors 1997. Proceedings of the IEEE Twenty-Fourth International Symposium on Compound Semiconductors, 1998

ABSTRACT n+ regrown source-drain regions have been used for AlGaN/GaN MODFETs to obtain a low-res... more ABSTRACT n+ regrown source-drain regions have been used for AlGaN/GaN MODFETs to obtain a low-resistance ohmic contact and clear-cut ohmic boundaries which will potentially facilitate fabrication of deep submicron-gate devices. The process consists: 1. Formation of the SiO 2 re-growth mask by E-beam evaporation and lift-off; 2. Removal of the AlGaN layer in the ohmic region by RIE; 3. n+ GaN re-growth in the MOCVD reactor; 4. Ohmic metal deposition and annealing. A transfer ohmic contact resistance of 0.44 Ω-mm was achieved. Much improved device performance was obtained with the new ohmic scheme over the conventional scheme with the same metalisation

Development of photoelectrochemical etching for gallium nitride device fabrication

Journal of Electronic Materials

Organic Light-Emitting Materials and Devices, 1997

ABSTRACT High performance photonic and electronic devices fabricate from conjugated polymers have... more ABSTRACT High performance photonic and electronic devices fabricate from conjugated polymers have been demonstrated, including light emitting diodes, photovoltaic cells, photodiodes, optocouplers, and thin film transistors. In some cases, performance parameters have been improved to levels comparable to or better than their inorganic counterparts.Notably absent from this list of semiconducting polymer devices is the polymer laser diode. As the first important step in exploring the feasibility of such laser diodes, optically pumped stimulated emission, gain, and lasing have recently been observed in over a dozen different semiconducting polymers representing a variety of molecular structures with emission wavelengths spanning the visible spectrum. Because of their strong absorption, high density of chromophores, and Stokes-shifted luminescence, luminescent semiconducting polymers have potential as low- threshold laser media and as active media in InGaN/polymer hybrid light emitting devices. We give details on an ongoing effort on optically pumped lasers using microcavities and distributed feedback (DFB) and suggest two routes toward fabricating laser diodes using semiconducting polymers. Initial results show that the lasing threshold for DFB laser is one order of magnitude lower than that of a microcavity laser using the same polymer under similar optical pumping conditions.

MOCVD growth of InGaN multiple quantum well LEDs and laser diodes

Compound Semiconductors 1997. Proceedings of the IEEE Twenty-Fourth International Symposium on Compound Semiconductors, 1998

The MOCVD growth of InGaN/GaN multiple quantum well (MQW) structures for blue LEDs and lasers has... more The MOCVD growth of InGaN/GaN multiple quantum well (MQW) structures for blue LEDs and lasers has been investigated. (1) The structural and optical properties of the layers have been characterized by X-ray diffraction and photoluminescence. (2) By incorporating an MQW structure as the active region in a GaN p-n diode, high-brightness light emitting diodes (LEDs) have been produced. Under a forward current of 20 mA, these devices emit 2.2 mW of power corresponding to an external quantum efficiency of 4.5%. (3) Room temperature (RT) pulsed operation of blue (420 nm) nitride based multi-quantum well (MQW) laser diodes grown on c-plane sapphire substrates with threshold current densities as low as 19 kA/cm2 were observed for 5×800 μm2 lasers with uncoated reactive ion etched (RIE) facets

MOCVD growth and fabrication of group-Ill nitrides for high-efficiency MQW LEDs

CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics, 1997

53rd Electronic Components and Technology Conference, 2003. Proceedings., 2003

LD … … driver chip PM fiber modulator AWG EDFA EDFA chirp comp. channel equalizer Raman 80km 80km... more LD … … driver chip PM fiber modulator AWG EDFA EDFA chirp comp. channel equalizer Raman 80km 80km AWG pin photodiode or APD TIA 4, 16, 32, 64, 80, 160 WDM channels SM fiber λ1 λ2 OC-192 LD

Blue InGaN MQW laser diodes on sapphire

Conference Proceedings. LEOS'98. 11th Annual Meeting. IEEE Lasers and Electro-Optics Society 1998 Annual Meeting (Cat. No.98CH36243), 1998

We report on the properties of blue InGaN MQW laser diodes fabricated using reactive ion etched f... more We report on the properties of blue InGaN MQW laser diodes fabricated using reactive ion etched facets on c-plane sapphire and cleaved facets on a-plane sapphire. We have also investigated the use of silicon doping in the quantum wells for the etched facet lasers

Pulsed- Operation of -Cleaved-Facet- InGaN Laser -Diodes

MRS Proceedings, 1997

... RK Sink*, AC Abare*, P. Kozodoy*, MP Mack", S. Keller", LA Coldren, SP DenB... more ... RK Sink*, AC Abare*, P. Kozodoy*, MP Mack", S. Keller", LA Coldren, SP DenBaars**, and JE Bowers* ECE Department, University of California ... with threshold voltages ranging from 50-90 V. Differential efficiencies are as high as 7% with maximum output powers greater than 50 ...

MOCVD Growth of High Output Power Ingan Multiple Quantum Well Light Emitting Diode

MRS Proceedings, 1997

ABSTRACT

Light-Tracking Optical Device and Application to Light Concentration

Point-Of-Use Disinfection of Drinking Water using Cationic Antimicrobial Surface Coatings

Proceedings of the Water Environment Federation, 2009

Low-dimensional resonant tunnelling and Coulomb blockade: a comparison of fabricated versus impurity confinement

Semiconductor Science and Technology, 1994

... Rev. B 41 5459 [4] Tewordt M, Law V J, Kelly M J, Newbury R, Pepper ;vi, Peacock DC, Frost JE... more ... Rev. B 41 5459 [4] Tewordt M, Law V J, Kelly M J, Newbury R, Pepper ;vi, Peacock DC, Frost JEF, Ritchie D A and Jones GA C 1990 J. Phys.: Condens. ... B r71 Asahi H. Tewordt M. Svme R T. Kelly M J. Law V J. _ _ Frost J E F, Ritchik DA, Jones GA C and Pepper i4 i99i Surj Sci. ...

Magnesium-doped gallium nitride for electronic and optoelectronic device applications

Magnesium doping of gallium nitride (GaN) for p-type conductivity is a crucial technology for a h... more Magnesium doping of gallium nitride (GaN) for p-type conductivity is a crucial technology for a host of optoelectronic and electronic device applications. The performance of many of these devices is presently limited by the various difficulties associated with Mg doping, both fundamental (such as the deep nature of the Mg acceptor) and technological (such as the problems in forming ohmic contacts). Both types of issues are addressed in this work. Heavy doping effects have been investigated in order to understand the consequences of the high dopant concentration typically employed; increased compensation and a reduction in the acceptor binding energy are among the effects observed. The compensation level is believed to limit the hole mobility in these films, and is found to depend on the choice of growth conditions; the results point to nitrogen vacancies as a likely candidate for one of the compensating donor species. The optimization of various processing procedures has also been addressed. These include the annealing procedure used to remove the hydrogen passivation as well as ohmic contact recipes. In addition, the electrical effects of plasma-induced damage to the p-type GaN surface are investigated; these effects are particularly important for bipolar transistor applications where a plasma etch is needed in order to reveal the base layer. The electrical characteristics of GaN p-n junctions formed both with and without dislocations are compared using the lateral epitaxial overgrowth technique; the dislocations are found to be the dominant leakage path in reverse-bias operation. The electrical consequences of the deep Mg acceptor are also addressed. These include the unusual nature of the low-frequency depletion region, and dispersion in the high-frequency depletion region due to the finite response time of the Mg acceptor. Finally, a novel scheme is presented that uses the strong polarization fields present in AlGaN/GaN superlattices to enhance the doping efficiency of the Mg acceptor. The polarization fields lead to hole accumulation in parallel sheets, resulting in a spatially-averaged hole concentration that is temperature-stable and significantly enhanced from that obtained in bulk films.

Photonic device with segmented absorption design

Self-Tracking Concentrator for Photovoltaics

CLEO: 2015, 2015

Magnesium-doped gallium nitride for electronic and optoelectronic device applications

... Thanks also go out to Lorenzo Faraone and Jarek Antoszewski at the University of Western Aust... more ... Thanks also go out to Lorenzo Faraone and Jarek Antoszewski at the University of Western Australia for preliminary investigations in this area. A number of close friends have made my time as a grad student much more enjoyable. ...

A first look at AlGaN/GaN HBTs

Method for the growth of P-type gallium nitride and its alloys

InGaN/GaN field emitters with a piezoelectrically-lowered surface barrier

Eleventh International Vacuum Microelectronics Conference. IVMC'98 (Cat. No.98TH8382), 1998

ABSTRACT The operating characteristics of field emitters are exponentially dependent on two devic... more ABSTRACT The operating characteristics of field emitters are exponentially dependent on two device parameters: the field enhancement factor and the surface energy barrier height. In addition to these device parameters, the practical use of field emitters as electron sources is dependent on the stability and uniformity of field emission. We have investigated field emission from GaN field emitters because GaN has a high resistance to sputtering and is chemically inert. One drawback of GaN field emitters is that they are not easily sharpened. Thus, to lower the operating voltage of GaN-based field emitters we have investigated the lowering of the surface energy barrier using a strained-layer of InGaN on GaN field. The piezoelectric polarization produced in the strained InGaN forms a dipole much like the dipole formed by coating a surface with an electropositive adsorbate

52nd Electronic Components and Technology Conference 2002. (Cat. No.02CH37345), 2002

We are manufacturing widely tunable laser diodes with an integrated high-speed electro-absorption... more We are manufacturing widely tunable laser diodes with an integrated high-speed electro-absorption modulator for metro and all-optical switching applications. The monolithic integration of the device combines the functions of high power laser light generation (> lOmW), wavelength tuning over the entire C-band (>loochannels on 5OGHz grid), and high speed signal modulation (>2.5Gbit/s). The laser section of the chip contains two sampled grating DBRs with a gain and a phase section between them. Wavelength tuning is achieved by current injection into the waveguide layers of the DBRs. Since electronics tuning and not thermal or mechanical tuning is employed wavelength tuning can be easily performed on a short time scale of less than lOms which is required for various applications. Even 4011s tuning speed is feasible with the appropriate driver electronics. Transmission experiments show less than 1dB power penalty over 200km of standard single mode fiber for all channels.

AlGaN/GaN MODFETs with low ohmic contact resistances by source/drain n/sup +/ re-growth

Compound Semiconductors 1997. Proceedings of the IEEE Twenty-Fourth International Symposium on Compound Semiconductors, 1998

ABSTRACT n+ regrown source-drain regions have been used for AlGaN/GaN MODFETs to obtain a low-res... more ABSTRACT n+ regrown source-drain regions have been used for AlGaN/GaN MODFETs to obtain a low-resistance ohmic contact and clear-cut ohmic boundaries which will potentially facilitate fabrication of deep submicron-gate devices. The process consists: 1. Formation of the SiO 2 re-growth mask by E-beam evaporation and lift-off; 2. Removal of the AlGaN layer in the ohmic region by RIE; 3. n+ GaN re-growth in the MOCVD reactor; 4. Ohmic metal deposition and annealing. A transfer ohmic contact resistance of 0.44 Ω-mm was achieved. Much improved device performance was obtained with the new ohmic scheme over the conventional scheme with the same metalisation

Development of photoelectrochemical etching for gallium nitride device fabrication

Journal of Electronic Materials

Organic Light-Emitting Materials and Devices, 1997

ABSTRACT High performance photonic and electronic devices fabricate from conjugated polymers have... more ABSTRACT High performance photonic and electronic devices fabricate from conjugated polymers have been demonstrated, including light emitting diodes, photovoltaic cells, photodiodes, optocouplers, and thin film transistors. In some cases, performance parameters have been improved to levels comparable to or better than their inorganic counterparts.Notably absent from this list of semiconducting polymer devices is the polymer laser diode. As the first important step in exploring the feasibility of such laser diodes, optically pumped stimulated emission, gain, and lasing have recently been observed in over a dozen different semiconducting polymers representing a variety of molecular structures with emission wavelengths spanning the visible spectrum. Because of their strong absorption, high density of chromophores, and Stokes-shifted luminescence, luminescent semiconducting polymers have potential as low- threshold laser media and as active media in InGaN/polymer hybrid light emitting devices. We give details on an ongoing effort on optically pumped lasers using microcavities and distributed feedback (DFB) and suggest two routes toward fabricating laser diodes using semiconducting polymers. Initial results show that the lasing threshold for DFB laser is one order of magnitude lower than that of a microcavity laser using the same polymer under similar optical pumping conditions.

MOCVD growth of InGaN multiple quantum well LEDs and laser diodes

Compound Semiconductors 1997. Proceedings of the IEEE Twenty-Fourth International Symposium on Compound Semiconductors, 1998

The MOCVD growth of InGaN/GaN multiple quantum well (MQW) structures for blue LEDs and lasers has... more The MOCVD growth of InGaN/GaN multiple quantum well (MQW) structures for blue LEDs and lasers has been investigated. (1) The structural and optical properties of the layers have been characterized by X-ray diffraction and photoluminescence. (2) By incorporating an MQW structure as the active region in a GaN p-n diode, high-brightness light emitting diodes (LEDs) have been produced. Under a forward current of 20 mA, these devices emit 2.2 mW of power corresponding to an external quantum efficiency of 4.5%. (3) Room temperature (RT) pulsed operation of blue (420 nm) nitride based multi-quantum well (MQW) laser diodes grown on c-plane sapphire substrates with threshold current densities as low as 19 kA/cm2 were observed for 5×800 μm2 lasers with uncoated reactive ion etched (RIE) facets

MOCVD growth and fabrication of group-Ill nitrides for high-efficiency MQW LEDs

CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics, 1997

53rd Electronic Components and Technology Conference, 2003. Proceedings., 2003

LD … … driver chip PM fiber modulator AWG EDFA EDFA chirp comp. channel equalizer Raman 80km 80km... more LD … … driver chip PM fiber modulator AWG EDFA EDFA chirp comp. channel equalizer Raman 80km 80km AWG pin photodiode or APD TIA 4, 16, 32, 64, 80, 160 WDM channels SM fiber λ1 λ2 OC-192 LD

Blue InGaN MQW laser diodes on sapphire

Conference Proceedings. LEOS'98. 11th Annual Meeting. IEEE Lasers and Electro-Optics Society 1998 Annual Meeting (Cat. No.98CH36243), 1998

We report on the properties of blue InGaN MQW laser diodes fabricated using reactive ion etched f... more We report on the properties of blue InGaN MQW laser diodes fabricated using reactive ion etched facets on c-plane sapphire and cleaved facets on a-plane sapphire. We have also investigated the use of silicon doping in the quantum wells for the etched facet lasers

Pulsed- Operation of -Cleaved-Facet- InGaN Laser -Diodes

MRS Proceedings, 1997

... RK Sink*, AC Abare*, P. Kozodoy*, MP Mack", S. Keller", LA Coldren, SP DenB... more ... RK Sink*, AC Abare*, P. Kozodoy*, MP Mack", S. Keller", LA Coldren, SP DenBaars**, and JE Bowers* ECE Department, University of California ... with threshold voltages ranging from 50-90 V. Differential efficiencies are as high as 7% with maximum output powers greater than 50 ...

MOCVD Growth of High Output Power Ingan Multiple Quantum Well Light Emitting Diode

MRS Proceedings, 1997

ABSTRACT