Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791709
G.J. Nott, E. Goldys
Using the real and imaginary dielectric constants of a GaAs/AlGaAs quantum well, both the absorption and refractive index of the structure were calculated. The imaginary dielectric constant was obtained by finding the contribution from each critical point in the density of states. The Kramers-Kronig transform of each contribution gave the corresponding real dielectric constant and these contributions were summed to give the material's total real dielectric constant. Absorption was found from the imaginary dielectric constant and fitted to experimental spectra. All contributions from confined and continuum transitions were considered in the subsequent calculation of refractive index with the resulting spectrum being comparable to published data.
{"title":"Accurate modelling of absorption and refractive index in a GaAs/AlGaAs quantum well","authors":"G.J. Nott, E. Goldys","doi":"10.1109/COMMAD.1998.791709","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791709","url":null,"abstract":"Using the real and imaginary dielectric constants of a GaAs/AlGaAs quantum well, both the absorption and refractive index of the structure were calculated. The imaginary dielectric constant was obtained by finding the contribution from each critical point in the density of states. The Kramers-Kronig transform of each contribution gave the corresponding real dielectric constant and these contributions were summed to give the material's total real dielectric constant. Absorption was found from the imaginary dielectric constant and fitted to experimental spectra. All contributions from confined and continuum transitions were considered in the subsequent calculation of refractive index with the resulting spectrum being comparable to published data.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116608811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791661
L. Fu, H. Tan, C. Jagadish, M. Johnston, M. Gal
As and H irradiation with subsequent thermal annealing were used to investigate the intermixing of InGaAs/GaAs and InGaAs/AlGaAs quantum wells (QWs). Large photoluminescence (PL) energy shifts were observed in both materials, Due to dynamic annealing in AlGaAs and the presence of Al in the barriers, the InGaAs/AlGaAs samples showed better PL intensities recovery and larger energy shifts than the InGaAs/GaAs samples after both As and H irradiation. Larger energy shifts were obtained for As irradiation at lower doses than when compared to H irradiation, However, at higher doses H irradiation resulted in higher energy shift than As irradiation, Results of the effect of irradiation temperature showed that higher shift could be obtained with increasing temperature for As irradiation at lower doses while for H irradiation, implant temperature had little effect.
{"title":"Quantum well intermixing in InGaAs/(Al)GaAs by As and H irradiation","authors":"L. Fu, H. Tan, C. Jagadish, M. Johnston, M. Gal","doi":"10.1109/COMMAD.1998.791661","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791661","url":null,"abstract":"As and H irradiation with subsequent thermal annealing were used to investigate the intermixing of InGaAs/GaAs and InGaAs/AlGaAs quantum wells (QWs). Large photoluminescence (PL) energy shifts were observed in both materials, Due to dynamic annealing in AlGaAs and the presence of Al in the barriers, the InGaAs/AlGaAs samples showed better PL intensities recovery and larger energy shifts than the InGaAs/GaAs samples after both As and H irradiation. Larger energy shifts were obtained for As irradiation at lower doses than when compared to H irradiation, However, at higher doses H irradiation resulted in higher energy shift than As irradiation, Results of the effect of irradiation temperature showed that higher shift could be obtained with increasing temperature for As irradiation at lower doses while for H irradiation, implant temperature had little effect.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121157477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791603
Seong-Il Kim, H. Tan, C. Jagadish, L. Dao, M. Gal
In this work, we have fabricated delta doped quantum wire structures with sharp tips and smooth side walls. Si delta doped InGaAs/GaAs quantum wire structures were grown on SiO/sub 2/ masked GaAs substrate by low pressure metalorganic chemical vapor deposition by using selective area epitaxy. The effects of the growth parameters such as growth rate, V/III ratio, growth temperature in selective epitaxy were investigated for GaAs/Al/sub 0.5/Ga/sub 0.5/As multilayer structures. To characterize and analyze the selectively grown structures, scanning electron microscopy and temperature dependent photoluminescence were used. The emission peak from quantum wires was observed at 975 nm. With increasing of temperature the emission intensity from side wall quantum wells decreased abruptly. But the intensity from quantum wires decreased slowly compared to that of side wall quantum wells and it became even stronger at about 50 K. The carrier capture processes also discussed.
{"title":"Fabrication and characterization of delta-doped In/sub 0.2/Ga/sub 0.8/As-GaAs quantum wire structures grown by MOCVD using selective area epitaxy","authors":"Seong-Il Kim, H. Tan, C. Jagadish, L. Dao, M. Gal","doi":"10.1109/COMMAD.1998.791603","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791603","url":null,"abstract":"In this work, we have fabricated delta doped quantum wire structures with sharp tips and smooth side walls. Si delta doped InGaAs/GaAs quantum wire structures were grown on SiO/sub 2/ masked GaAs substrate by low pressure metalorganic chemical vapor deposition by using selective area epitaxy. The effects of the growth parameters such as growth rate, V/III ratio, growth temperature in selective epitaxy were investigated for GaAs/Al/sub 0.5/Ga/sub 0.5/As multilayer structures. To characterize and analyze the selectively grown structures, scanning electron microscopy and temperature dependent photoluminescence were used. The emission peak from quantum wires was observed at 975 nm. With increasing of temperature the emission intensity from side wall quantum wells decreased abruptly. But the intensity from quantum wires decreased slowly compared to that of side wall quantum wells and it became even stronger at about 50 K. The carrier capture processes also discussed.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121448964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791702
W. Lu, X. Liu, X. Chen, G. Shi, Y. Qiao, S. Shen, Y. Fu, M. Willander
In this paper we present the study on the surface doping behavior of Si on the GaAs [100] surface by using modulated photo-reflection spectroscopy technique at room temperature. With the envelope wave function model combined with experimental interband transition energy in the delta-doping induced potential the highest carrier concentration in the surface doping GaAs sample is obtained around 1/spl times/10/sup 14/ cm/sup -2/.
{"title":"Interband transition in surface delta-doped GaAs studied by photo-reflectance","authors":"W. Lu, X. Liu, X. Chen, G. Shi, Y. Qiao, S. Shen, Y. Fu, M. Willander","doi":"10.1109/COMMAD.1998.791702","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791702","url":null,"abstract":"In this paper we present the study on the surface doping behavior of Si on the GaAs [100] surface by using modulated photo-reflection spectroscopy technique at room temperature. With the envelope wave function model combined with experimental interband transition energy in the delta-doping induced potential the highest carrier concentration in the surface doping GaAs sample is obtained around 1/spl times/10/sup 14/ cm/sup -2/.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124703925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791671
V. Boros, A. Rakić, M. Majewski
A novel computer-controlled system for characterisation of vertical cavity surface emitting lasers (VCSELs) is presented. The automation process enables intensive analysis of VCSEL transverse modes in addition to determination of conventional laser characteristics and figures of merit. Analysis of measurements provides insight into the design issues affecting optimal coupling to fibres and interbeam crosstalk in free space interconnects. To illustrate the process we provide samples of program code and experiment results.
{"title":"Measurement automation for characterising vertical cavity surface emitting lasers","authors":"V. Boros, A. Rakić, M. Majewski","doi":"10.1109/COMMAD.1998.791671","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791671","url":null,"abstract":"A novel computer-controlled system for characterisation of vertical cavity surface emitting lasers (VCSELs) is presented. The automation process enables intensive analysis of VCSEL transverse modes in addition to determination of conventional laser characteristics and figures of merit. Analysis of measurements provides insight into the design issues affecting optimal coupling to fibres and interbeam crosstalk in free space interconnects. To illustrate the process we provide samples of program code and experiment results.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127152259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791681
S. Hinckley, E. Gluszak
The flux method has been used to simulate the effect of depletion layer and grain boundary recombination on the performance of polycrystalline semiconductor photovoltaic devices under solar illumination. Results are presented for a polycrystalline n/sup +/-p silicon homojunction solar cell, and an n/sup +/-p CdS/CuInSe/sub 2/ heterojunction solar cell.
{"title":"The effects of depletion layer recombination in polycrystalline photovoltaic devices under illumination","authors":"S. Hinckley, E. Gluszak","doi":"10.1109/COMMAD.1998.791681","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791681","url":null,"abstract":"The flux method has been used to simulate the effect of depletion layer and grain boundary recombination on the performance of polycrystalline semiconductor photovoltaic devices under solar illumination. Results are presented for a polycrystalline n/sup +/-p silicon homojunction solar cell, and an n/sup +/-p CdS/CuInSe/sub 2/ heterojunction solar cell.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122166027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791707
H. Dou, W. Lu, Xiaoshuang Chen, Ning Li, S. Shen, G. Li, C. Jagadish, Y. Fu, M. Willander
Zn /spl delta/-doped GaAs was investigated by photomodulation spectroscopy. At the high-energy side of the fundamental band gap of GaAs, two transitions were observed, The potential and energy structure of Zn /spl delta/-doped GaAs were calculated self-consistently using effective mass approximation. The absorption coefficient of Zn /spl delta/-doped GaAs and its differential were also calculated. The energy positions of transitions from the first level of heavy and light holes are obtained respectively, The experimental and calculated results are in good agreement.
{"title":"Photomodulation spectroscopy of Zn /spl delta/-doped GaAs","authors":"H. Dou, W. Lu, Xiaoshuang Chen, Ning Li, S. Shen, G. Li, C. Jagadish, Y. Fu, M. Willander","doi":"10.1109/COMMAD.1998.791707","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791707","url":null,"abstract":"Zn /spl delta/-doped GaAs was investigated by photomodulation spectroscopy. At the high-energy side of the fundamental band gap of GaAs, two transitions were observed, The potential and energy structure of Zn /spl delta/-doped GaAs were calculated self-consistently using effective mass approximation. The absorption coefficient of Zn /spl delta/-doped GaAs and its differential were also calculated. The energy positions of transitions from the first level of heavy and light holes are obtained respectively, The experimental and calculated results are in good agreement.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129638000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791613
G. Parish, S. Keller, P. Kozodoy, J. Ibbetson, H. Marchand, P. Fini, S. Fleischer, S. Denbaars, U. Mishra, E. Tarsa
Solar-blind ultraviolet photodiodes with a cutoff wavelength of 285 nm were fabricated on Laterally Epitaxially Overgrown (LEO) GaN grown by metalorganic chemical vapour deposition (MOCVD). Current-voltage measurements of the diodes exhibited dark current densities as low as 10 nA/cm/sup 2/ at -5 V. Spectral response measurements revealed peak responsivities of up to 0.05 A/W. For comparison, diodes were fabricated using the same p-i-n structure deposited on dislocated GaN. These diodes had dark current densities over seven orders of magnitude higher. In addition, whilst having comparable peak responsivities, the diodes on dislocated GaN had a less sharp cutoff.
{"title":"Low dark current p-i-n (Al,Ga)N-based solar-blind UV detectors on laterally epitaxially overgrown GaN","authors":"G. Parish, S. Keller, P. Kozodoy, J. Ibbetson, H. Marchand, P. Fini, S. Fleischer, S. Denbaars, U. Mishra, E. Tarsa","doi":"10.1109/COMMAD.1998.791613","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791613","url":null,"abstract":"Solar-blind ultraviolet photodiodes with a cutoff wavelength of 285 nm were fabricated on Laterally Epitaxially Overgrown (LEO) GaN grown by metalorganic chemical vapour deposition (MOCVD). Current-voltage measurements of the diodes exhibited dark current densities as low as 10 nA/cm/sup 2/ at -5 V. Spectral response measurements revealed peak responsivities of up to 0.05 A/W. For comparison, diodes were fabricated using the same p-i-n structure deposited on dislocated GaN. These diodes had dark current densities over seven orders of magnitude higher. In addition, whilst having comparable peak responsivities, the diodes on dislocated GaN had a less sharp cutoff.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132985799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791598
J. Simmons, B. Elenkrig, S. Smetona, B. Takasaki, J.D. Evans
The series resistance of InGaAsP/InP Multiple Quantum Well ridge waveguide laser diodes is investigated experimentally over a wide temperature range for both Fabry-Perot and Distributed Feedback type lasers. From the temperature dependence of the series resistance is found that it is defined mostly by the resistance of heterobarriers, although the semiconductor bulk resistance is also found to be a substantial part of ridge waveguide laser series resistance. The effect of the laser series resistance on its performance characteristics is investigated. The theoretically predicted strong correlation between the series resistance and laser maximum operating power is confirmed experimentally. The ways of reducing of series resistance are discussed.
{"title":"Series resistance and its effect on the maximum output power of 1.5 /spl mu/m strained-layer multiple-quantum-well ridge waveguide InGaAsP lasers","authors":"J. Simmons, B. Elenkrig, S. Smetona, B. Takasaki, J.D. Evans","doi":"10.1109/COMMAD.1998.791598","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791598","url":null,"abstract":"The series resistance of InGaAsP/InP Multiple Quantum Well ridge waveguide laser diodes is investigated experimentally over a wide temperature range for both Fabry-Perot and Distributed Feedback type lasers. From the temperature dependence of the series resistance is found that it is defined mostly by the resistance of heterobarriers, although the semiconductor bulk resistance is also found to be a substantial part of ridge waveguide laser series resistance. The effect of the laser series resistance on its performance characteristics is investigated. The theoretically predicted strong correlation between the series resistance and laser maximum operating power is confirmed experimentally. The ways of reducing of series resistance are discussed.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130586051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791628
W. Cheung, P. Edwards, G. N. French
We performed measurements on a number of pre-production DH LEDs biased from 1 to 10 mA and, for each case, we obtained a broad-band input impedance plot which gives both magnitude and phase as a function of frequency. We deduced from these plots the carrier lifetime, differential diode resistance, diffusion capacitance, parasitic resistance, and the ideality factor of each diode. The parameters were then used in the equivalent circuit to calculate the modelled input impedance of the device which was then compared with the measured result. There is good agreement over a wide frequency range, at least up to the frequency equal to 1/(carrier lifetime). The existence of a maximum phase lag previously noticed in single-port laser measurements is fully accounted for in our model.
{"title":"Determination of LED equivalent circuits using network analyser measurements","authors":"W. Cheung, P. Edwards, G. N. French","doi":"10.1109/COMMAD.1998.791628","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791628","url":null,"abstract":"We performed measurements on a number of pre-production DH LEDs biased from 1 to 10 mA and, for each case, we obtained a broad-band input impedance plot which gives both magnitude and phase as a function of frequency. We deduced from these plots the carrier lifetime, differential diode resistance, diffusion capacitance, parasitic resistance, and the ideality factor of each diode. The parameters were then used in the equivalent circuit to calculate the modelled input impedance of the device which was then compared with the measured result. There is good agreement over a wide frequency range, at least up to the frequency equal to 1/(carrier lifetime). The existence of a maximum phase lag previously noticed in single-port laser measurements is fully accounted for in our model.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"275 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133133383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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