F. Demangeot, J. Frandon, M. Renucci, B. Beaumont, P. Gibart
GaN layers grown on sapphire (0001) substrates were studied at room temperature by Raman Spectroscopy. Directional dependance of frequency and polarization properties of the extraordinary modes, resulting from the anisotropic wurtzite, was evidenced by macro- and micro-Raman measurements. Second order Raman spectra were recorded and their completely symmetric component was analyzed in terms of phonon density of states. Due to the lack of phonon spectrum calculations, use was made of available q-dispersion curves of the closely related ZnO compound for phonon assignment.
{"title":"Phonon dispersion in gallium nitride","authors":"F. Demangeot, J. Frandon, M. Renucci, B. Beaumont, P. Gibart","doi":"10.1109/SIM.1996.570889","DOIUrl":"https://doi.org/10.1109/SIM.1996.570889","url":null,"abstract":"GaN layers grown on sapphire (0001) substrates were studied at room temperature by Raman Spectroscopy. Directional dependance of frequency and polarization properties of the extraordinary modes, resulting from the anisotropic wurtzite, was evidenced by macro- and micro-Raman measurements. Second order Raman spectra were recorded and their completely symmetric component was analyzed in terms of phonon density of states. Due to the lack of phonon spectrum calculations, use was made of available q-dispersion curves of the closely related ZnO compound for phonon assignment.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134002014","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}
Z. Fang, D. Look, S. Kuisma, K. Saarinen, P. Hautojarvi
Point defects and the main electron traps in undoped semi-insulating GaAs grown by vertical gradient freeze and high- and low-pressure liquid encapsulated Czochralski techniques have been studied by positron annihilation (PAS) and thermally stimulated current (TSC) spectroscopies, respectively. We find good correlations between the concentrations of the TSC traps T/sub 2/ (0.63 eV) and T/sub 5/ (0.35 eV), and the PAS identified-defects As/sub Ga/ and V/sub As/, respectively. A good correlation between the concentration of intrinsic acceptors (V/sub Ga/ and Ga/sub As/) measured by PAS, and the total acceptor concentration measured by infrared absorption, is also found.
{"title":"Point defects in undoped semi-insulating GaAs: correlation between thermally stimulated current and positron annihilation spectroscopies","authors":"Z. Fang, D. Look, S. Kuisma, K. Saarinen, P. Hautojarvi","doi":"10.1109/SIM.1996.570928","DOIUrl":"https://doi.org/10.1109/SIM.1996.570928","url":null,"abstract":"Point defects and the main electron traps in undoped semi-insulating GaAs grown by vertical gradient freeze and high- and low-pressure liquid encapsulated Czochralski techniques have been studied by positron annihilation (PAS) and thermally stimulated current (TSC) spectroscopies, respectively. We find good correlations between the concentrations of the TSC traps T/sub 2/ (0.63 eV) and T/sub 5/ (0.35 eV), and the PAS identified-defects As/sub Ga/ and V/sub As/, respectively. A good correlation between the concentration of intrinsic acceptors (V/sub Ga/ and Ga/sub As/) measured by PAS, and the total acceptor concentration measured by infrared absorption, is also found.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134360309","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}
P. Kamiński, M. Pawłowski, R. Cwirko, M. Palczewska, R. Kozłowski
Deep levels in undoped semi-insulating (SI) GaAs and Fe-doped SI InP investigated by photoinduced transient spectroscopy (PITS). It is demonstrated that the resolution of this method can be improved by direct computer fitting of digitally recorded photocurrent decays.
{"title":"Characterisation of deep-level defects in semi-insulating GaAs and InP by high resolution photoinduced transient spectroscopy (HRPITS)","authors":"P. Kamiński, M. Pawłowski, R. Cwirko, M. Palczewska, R. Kozłowski","doi":"10.1109/SIM.1996.570926","DOIUrl":"https://doi.org/10.1109/SIM.1996.570926","url":null,"abstract":"Deep levels in undoped semi-insulating (SI) GaAs and Fe-doped SI InP investigated by photoinduced transient spectroscopy (PITS). It is demonstrated that the resolution of this method can be improved by direct computer fitting of digitally recorded photocurrent decays.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"26 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116215199","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}
R. Buhleier, J. Iehl, J. Collet, V. Bardinal, C. Fontaine, R. Legros
The temporal and spectral response of bulk GaAs Fabry-Perot microcavities have been investigated in the subpicosecond regime at room temperature. Time resolved reflectivity measurements show a strong reshaping of a Gaussian fs-pulse after reflection from a microcavity caused by group velocity dispersion. The pulse distortion agrees fairly well with model calculations using Fourier transform analysis. Time integrated degenerate four-wave mixing experiments show that response times of the cavity as short as 300 fs were achieved.
{"title":"Subpicosecond response of GaAs Fabry-Perot microcavities","authors":"R. Buhleier, J. Iehl, J. Collet, V. Bardinal, C. Fontaine, R. Legros","doi":"10.1109/SIM.1996.571110","DOIUrl":"https://doi.org/10.1109/SIM.1996.571110","url":null,"abstract":"The temporal and spectral response of bulk GaAs Fabry-Perot microcavities have been investigated in the subpicosecond regime at room temperature. Time resolved reflectivity measurements show a strong reshaping of a Gaussian fs-pulse after reflection from a microcavity caused by group velocity dispersion. The pulse distortion agrees fairly well with model calculations using Fourier transform analysis. Time integrated degenerate four-wave mixing experiments show that response times of the cavity as short as 300 fs were achieved.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124808577","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}
K. Rezzoug, F. Ducroquet, G. Guillot, L. Giraudet, J.P. Praseuth
Electron traps in AlInAs/In/sub .52/(Ca/sub 1-x/Al/sub x/)/sub .48/As (x=0.3) heterostructures are investigated by deep level transient spectroscopy. Two dominant traps with activation energies of 0.31 and 0.59 eV are observed in quaternary and ternary layers respectively. Both these levels are supposed to be intrinsic defects from the same origin. Another defect at E/sub c/-0.4 eV is detected at the AlInAs/InCaAlAs interface. The concentration of this trap is found to be non uniformly distributed on the wafer and possible impurity contamination is suggested.
{"title":"Deep trap characterization of Al./sub 48/In./sub 52/As/In/sub .52/(Ga/sub .7/Al/sub .3/)/sub .48/As heterostructures","authors":"K. Rezzoug, F. Ducroquet, G. Guillot, L. Giraudet, J.P. Praseuth","doi":"10.1109/SIM.1996.571102","DOIUrl":"https://doi.org/10.1109/SIM.1996.571102","url":null,"abstract":"Electron traps in AlInAs/In/sub .52/(Ca/sub 1-x/Al/sub x/)/sub .48/As (x=0.3) heterostructures are investigated by deep level transient spectroscopy. Two dominant traps with activation energies of 0.31 and 0.59 eV are observed in quaternary and ternary layers respectively. Both these levels are supposed to be intrinsic defects from the same origin. Another defect at E/sub c/-0.4 eV is detected at the AlInAs/InCaAlAs interface. The concentration of this trap is found to be non uniformly distributed on the wafer and possible impurity contamination is suggested.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128706960","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}
The d.c. and a.c. electrical conduction has been studied in GaAs layer grown by molecular beam epitaxy between 150/spl deg/C and 400/spl deg/C. It is found that the admittance versus frequency, Y(/spl omega/), exhibits a universal behaviour. At low frequencies Y(/spl omega/) is constant, then exhibits a minimum at /spl omega//sub m/. At high frequencies Y(/spl omega/) varies linearly as /spl omega/ showing that conduction occurs via hopping. The temperature dependence of Y(0) indicates that this hopping conduction occurs in a partially filled band related to EL2 defects, the direct relationship between /spl omega//sub m/ and Y(0) demonstrates the existence of a percolation regime, i.e. of a conduction limited by insulating regions which we attribute to space charge regions developed around as precipitates.
{"title":"Characterization of conduction in LTG-GaAs","authors":"J. Bourgoin, K. Khirouni, J. Nagle","doi":"10.1109/SIM.1996.570870","DOIUrl":"https://doi.org/10.1109/SIM.1996.570870","url":null,"abstract":"The d.c. and a.c. electrical conduction has been studied in GaAs layer grown by molecular beam epitaxy between 150/spl deg/C and 400/spl deg/C. It is found that the admittance versus frequency, Y(/spl omega/), exhibits a universal behaviour. At low frequencies Y(/spl omega/) is constant, then exhibits a minimum at /spl omega//sub m/. At high frequencies Y(/spl omega/) varies linearly as /spl omega/ showing that conduction occurs via hopping. The temperature dependence of Y(0) indicates that this hopping conduction occurs in a partially filled band related to EL2 defects, the direct relationship between /spl omega//sub m/ and Y(0) demonstrates the existence of a percolation regime, i.e. of a conduction limited by insulating regions which we attribute to space charge regions developed around as precipitates.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127682128","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}
M. Neubert, M. Seifert, P. Rudolph, K. Trompa, M. Pietsch
The purpose of this paper is to show the current stage of development of the Vapour Pressure Controlled Czochralski Method (VCZ) at the Institute of Crystal Growth (IKZ) in Berlin. First 3" s.i. GaAs crystals, grown in our laboratory, will be presented. The paper briefly summarizes investigations on i) crystal perfection i.e., etch pit density (EPD), cell structure, precipitates and, ii) electrical data, The properties of the crystals are acceptable for s.i. GaAs. An average EPD in the range from 1 to 2/spl times/10/sup 4/ cm/sup -2/ is just achieved but, does not yet match the requirements of very low EPD material.
{"title":"First results of s.i. GaAs single crystal growth applying the vapour pressure controlled Czochralski method","authors":"M. Neubert, M. Seifert, P. Rudolph, K. Trompa, M. Pietsch","doi":"10.1109/SIM.1996.570868","DOIUrl":"https://doi.org/10.1109/SIM.1996.570868","url":null,"abstract":"The purpose of this paper is to show the current stage of development of the Vapour Pressure Controlled Czochralski Method (VCZ) at the Institute of Crystal Growth (IKZ) in Berlin. First 3\" s.i. GaAs crystals, grown in our laboratory, will be presented. The paper briefly summarizes investigations on i) crystal perfection i.e., etch pit density (EPD), cell structure, precipitates and, ii) electrical data, The properties of the crystals are acceptable for s.i. GaAs. An average EPD in the range from 1 to 2/spl times/10/sup 4/ cm/sup -2/ is just achieved but, does not yet match the requirements of very low EPD material.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116332295","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}
Comparisons have been made of the frequency dependence of the backgate admittance of GaAs structures prepared by MBE on undoped buffer layers prepared at high and low temperatures and of ion implanted structures. A model is offered to explain extra capacitive currents at low frequencies. Inductive and negative resistance behaviours which appear to be related have not been explained. None of these phenomena were apparent in the LT based structures.
{"title":"Observations of low frequency admittance between isolated GaAs structures formed by ion implantation and by epitaxy on epitaxial buffer layers prepared at high and low temperatures","authors":"F. Boroumand, A. Khalid, M. Hopkinson, J. Swanson","doi":"10.1109/SIM.1996.570876","DOIUrl":"https://doi.org/10.1109/SIM.1996.570876","url":null,"abstract":"Comparisons have been made of the frequency dependence of the backgate admittance of GaAs structures prepared by MBE on undoped buffer layers prepared at high and low temperatures and of ion implanted structures. A model is offered to explain extra capacitive currents at low frequencies. Inductive and negative resistance behaviours which appear to be related have not been explained. None of these phenomena were apparent in the LT based structures.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125292567","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}
In this paper we report on the optimization of the MBE growth process for obtaining semi-insulating LT-GaAs layers applied in vertical-cavity surface-emitting-lasers. The technological conditions for growing LT-GaAs layers have been found and test processes for growing the laser structure at the optimum conditions have been performed. Although numerous optoelectronic applications of LT GaAs have been demonstrated we believe that this is one of the rare cases when LT GaAs has been used in semiconductor laser technology.
{"title":"LT GaAs semi-insulating layers applied in vertical-cavity surface-emitting lasers","authors":"K. Reginski, A. Malag, D. Radomska, M. Bugajski","doi":"10.1109/SIM.1996.571113","DOIUrl":"https://doi.org/10.1109/SIM.1996.571113","url":null,"abstract":"In this paper we report on the optimization of the MBE growth process for obtaining semi-insulating LT-GaAs layers applied in vertical-cavity surface-emitting-lasers. The technological conditions for growing LT-GaAs layers have been found and test processes for growing the laser structure at the optimum conditions have been performed. Although numerous optoelectronic applications of LT GaAs have been demonstrated we believe that this is one of the rare cases when LT GaAs has been used in semiconductor laser technology.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126736908","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}
S. Sanchez, T. Cloitre, P. Bigenwald, A. Chergui, B. Honerlague, R. Aulombard
Graded index separate confinement heterostructures (GRIN-SCH) for microgun blue-green laser were grown by MOVPE. A first study was carried out using selenium hydride, dimethyl cadmium and two dimethylzine adducts as Se, Cd and Zn precursor respectively. This combination leads to intense prereactions and poor layer morphology. To limit this problem we have then used the tetrahydrothiophene:dimethylcadmium adduct. We have first investigated the quality of thick ZnCdSe layers grown using this adduct. GRIN-SCH structures grown using the two cadmium metalorganics were studied using photoluminescence and optical pumping experiments. Stimulated emission was observed for the two kind of samples.
{"title":"ZnCdSe-ZnSe heterostructures grown by MOVPE: influence of the cadmium precursor","authors":"S. Sanchez, T. Cloitre, P. Bigenwald, A. Chergui, B. Honerlague, R. Aulombard","doi":"10.1109/SIM.1996.570914","DOIUrl":"https://doi.org/10.1109/SIM.1996.570914","url":null,"abstract":"Graded index separate confinement heterostructures (GRIN-SCH) for microgun blue-green laser were grown by MOVPE. A first study was carried out using selenium hydride, dimethyl cadmium and two dimethylzine adducts as Se, Cd and Zn precursor respectively. This combination leads to intense prereactions and poor layer morphology. To limit this problem we have then used the tetrahydrothiophene:dimethylcadmium adduct. We have first investigated the quality of thick ZnCdSe layers grown using this adduct. GRIN-SCH structures grown using the two cadmium metalorganics were studied using photoluminescence and optical pumping experiments. Stimulated emission was observed for the two kind of samples.","PeriodicalId":391894,"journal":{"name":"Proceedings of Semiconducting and Semi-Insulating Materials Conference","volume":"30 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126738898","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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