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Donor states in Te-Doped GaAsl−xPx
455
ABSTRACTS
Vol. 93, No. 5 have different decay rates and that samples A,B result in equilibrium concentrations. The thermal activation energy of TD annihilation is found to be equal to (2.31+0.14)eV. We introduce a TD-model in which the various TDx centers are represented by oxygen clusters of different sizes (4 to 24 atoms) and which reproduces our exoerimental TD annihilation data.
STARK-BROADENING BY INHOMOGENEOUS ELECTRIC FIELD IN COMPENSATED GERMANIUM Y.Harada, K.Fujii, T.Ohyama, E.E.Haller* and K.ltoh t Department of Physics, College of General Education, Osaka University, Toyonaka, Osaka 560, Japan *Lawrence Berkeley Laboratory, University of California, Berkley, CA 94720,USA We have observed the Stark broadening by imhomogeneous coulomb fields in compensated p-type Ge through far-infrared absorption measurements. Various transmutation-doped samples with different compensation ratio, K, are prepared. In particular, the magneto-optical absorption linewidth for Ga acceptor has been measured as a function of the intensity of excitation light. The full width at half maximum (FWHM) for the absorption lines decreases as the intensity of photopulse excitation with the above-band gap energy increases. In the case of highly compensated samples, the FWHM without photoexcitation is several times wider than that under photopulse excitation. It is considered that this has its origin in the Stark broadening by coulomb fields due to inhomogeneous distribution of the ionized impurities in the crystal. In explanation of the broadening mechanism, the approach based on the Monte Carlo simulation, concerned with the inhomogreneous coulomb field induced by ionized impurities, is employed.
S P E C T R O S C O P I C S T U D Y OF B E R Y L L I U M R E L A T E D A C C E P T O R S IN S I L I C O N L. T. Ho, F. Y. Lin, M. J. Wu, a n d W. J. L i n I n s t i t u t e of P h y s i c s Academia Sinica N a n k a n g , Taipei, T a i w a n R e p u b l i c of C h i n a P r e v i o u s study (1-5) i n d i c a t e s t h a t beryllium, when thermally diffused into silicon, i n t r o d u c e s s e v e r a l a c c e p t o r centers. R e c e n t l y , we r e - m e a s u r e d the e x c i t a t i o n spectra of five b e r y l l i u m r e l a t e d acceptors. O u r r e s u l t s i n c l u d i n g some n e w features will be presented. The m o s t s i g n i f i c a n t o n e is t h a t some
e x c i t a t i o n lines o b s e r v e d have a very c l e a r d o u b l e t or e v e n t r i p l e t s t r u c t u r e i n d i c a t i n g the e x i s t e n c e of a m u l t i l e v e l g r o u n d state in g o o d a g r e e m e n t w i t h the t h e o r e t i c a l p r e d i c t i o n for a d o u b l e acceptor. (1) R. K. Crouch, J. B. Robertson, and T. E. Gilmer, Jr., Phys. Rev. B5, 3111 (1972). (2) M. K l e v e r m a n a n d H. G. Grimmeiss, Semicond. Sci. T e c h n o l 1, 45 (1986). (3) K. M u r o and A. J. Sievers, Phys. Rev. Lett. 57, 897 (1986). (4) R. E. Peale, K. Muro, and A. J. Sievers, Phys. Rev. B41, 5881 (1990). (5) J. N. Heyman, E. E. Ealler, and A. Giesekus, Phys. Rev. B44, 12769
(1991). W o r k p a r t i a l l y s u p p o r t e d by the N a t i o n a l S c i e n c e C o u n c i l of the R e p u b l i c of C h i n a G r a n t No. N S C 820208-M-001-090.
DONOR STATES IN Te-DOPED GaAsl..xPx Q S. Huang, J. Y Kang, and Y. C. Zhang Depamnmt of Physics,Yaan'~ University,>flamen, and NationalLaboratoryfor IrYmredPhysics, Shanghai, P R China We investigated the donor states in Te-doped GaAsP by high resolutionDLTS under both dark and illumination conditions and photocapacitance (PHCAP) methods. Three distinct dectron errfission peaks of A, B, and C sirmfltamouslyappeared in light illu~ation DLTS of all samples covefa~ comt~tions of the direct ard ~ r e c t gaps. Their activation energies were independmt of corng:~on and were 0.18, 0.28, and 0.38 eV for levets A, B, and C, mspecfiv~ Among them the signal amplitudeof peak A was the largest, but B was hrger and smaner than C in c~rect and indirect gap samp~ resp~iv~. The capture~ oft~ three levds were also obtain~ In PHCAP exlxtiments the B and C levets were omr,.etm-,ttedort The spectra of dectron p h o t ~ cross sections of B and C were n'gamred, A good fit of tl~ spectral shape with theory gave the opticaltheslx~ energie~ of 1.25 eV for B and 1.70eV for C and the localvl~afioml nxxte energies of 5- 10 meV dosed to tl~ TA ~ at ~ zo~ in c r ~ ~ c ~ . She ~ c t c ~ s ~ san~ ~ at p h o ~ e ~ i e s of ~ s~-~ values also appeared in steady-state PHCAP. Extxtim~ shows that three donor states are indelx~ent charge states. It seems that they are three DX-like centers originated fr~n different snuOx~ configurations. The eximmce of two or more DX-like centers is suggestedrecentlyin A1CraAs.1,2 1D. J. Chadi,Phys. Rev. B 46, 6777 (1992). 2Q. S, t-ham~ J. Y. Kang et al., J. Appl. Phys. 71, 5952 (1992);Phys. Rev. B 47, 13 215 0993).
ABSTRACTS
Vol. 93, No. 5 have different decay rates and that samples A,B result in equilibrium concentrations. The thermal activation energy of TD annihilation is found to be equal to (2.31+0.14)eV. We introduce a TD-model in which the various TDx centers are represented by oxygen clusters of different sizes (4 to 24 atoms) and which reproduces our exoerimental TD annihilation data.
STARK-BROADENING BY INHOMOGENEOUS ELECTRIC FIELD IN COMPENSATED GERMANIUM Y.Harada, K.Fujii, T.Ohyama, E.E.Haller* and K.ltoh t Department of Physics, College of General Education, Osaka University, Toyonaka, Osaka 560, Japan *Lawrence Berkeley Laboratory, University of California, Berkley, CA 94720,USA We have observed the Stark broadening by imhomogeneous coulomb fields in compensated p-type Ge through far-infrared absorption measurements. Various transmutation-doped samples with different compensation ratio, K, are prepared. In particular, the magneto-optical absorption linewidth for Ga acceptor has been measured as a function of the intensity of excitation light. The full width at half maximum (FWHM) for the absorption lines decreases as the intensity of photopulse excitation with the above-band gap energy increases. In the case of highly compensated samples, the FWHM without photoexcitation is several times wider than that under photopulse excitation. It is considered that this has its origin in the Stark broadening by coulomb fields due to inhomogeneous distribution of the ionized impurities in the crystal. In explanation of the broadening mechanism, the approach based on the Monte Carlo simulation, concerned with the inhomogreneous coulomb field induced by ionized impurities, is employed.
S P E C T R O S C O P I C S T U D Y OF B E R Y L L I U M R E L A T E D A C C E P T O R S IN S I L I C O N L. T. Ho, F. Y. Lin, M. J. Wu, a n d W. J. L i n I n s t i t u t e of P h y s i c s Academia Sinica N a n k a n g , Taipei, T a i w a n R e p u b l i c of C h i n a P r e v i o u s study (1-5) i n d i c a t e s t h a t beryllium, when thermally diffused into silicon, i n t r o d u c e s s e v e r a l a c c e p t o r centers. R e c e n t l y , we r e - m e a s u r e d the e x c i t a t i o n spectra of five b e r y l l i u m r e l a t e d acceptors. O u r r e s u l t s i n c l u d i n g some n e w features will be presented. The m o s t s i g n i f i c a n t o n e is t h a t some
e x c i t a t i o n lines o b s e r v e d have a very c l e a r d o u b l e t or e v e n t r i p l e t s t r u c t u r e i n d i c a t i n g the e x i s t e n c e of a m u l t i l e v e l g r o u n d state in g o o d a g r e e m e n t w i t h the t h e o r e t i c a l p r e d i c t i o n for a d o u b l e acceptor. (1) R. K. Crouch, J. B. Robertson, and T. E. Gilmer, Jr., Phys. Rev. B5, 3111 (1972). (2) M. K l e v e r m a n a n d H. G. Grimmeiss, Semicond. Sci. T e c h n o l 1, 45 (1986). (3) K. M u r o and A. J. Sievers, Phys. Rev. Lett. 57, 897 (1986). (4) R. E. Peale, K. Muro, and A. J. Sievers, Phys. Rev. B41, 5881 (1990). (5) J. N. Heyman, E. E. Ealler, and A. Giesekus, Phys. Rev. B44, 12769
(1991). W o r k p a r t i a l l y s u p p o r t e d by the N a t i o n a l S c i e n c e C o u n c i l of the R e p u b l i c of C h i n a G r a n t No. N S C 820208-M-001-090.
DONOR STATES IN Te-DOPED GaAsl..xPx Q S. Huang, J. Y Kang, and Y. C. Zhang Depamnmt of Physics,Yaan'~ University,>flamen, and NationalLaboratoryfor IrYmredPhysics, Shanghai, P R China We investigated the donor states in Te-doped GaAsP by high resolutionDLTS under both dark and illumination conditions and photocapacitance (PHCAP) methods. Three distinct dectron errfission peaks of A, B, and C sirmfltamouslyappeared in light illu~ation DLTS of all samples covefa~ comt~tions of the direct ard ~ r e c t gaps. Their activation energies were independmt of corng:~on and were 0.18, 0.28, and 0.38 eV for levets A, B, and C, mspecfiv~ Among them the signal amplitudeof peak A was the largest, but B was hrger and smaner than C in c~rect and indirect gap samp~ resp~iv~. The capture~ oft~ three levds were also obtain~ In PHCAP exlxtiments the B and C levets were omr,.etm-,ttedort The spectra of dectron p h o t ~ cross sections of B and C were n'gamred, A good fit of tl~ spectral shape with theory gave the opticaltheslx~ energie~ of 1.25 eV for B and 1.70eV for C and the localvl~afioml nxxte energies of 5- 10 meV dosed to tl~ TA ~ at ~ zo~ in c r ~ ~ c ~ . She ~ c t c ~ s ~ san~ ~ at p h o ~ e ~ i e s of ~ s~-~ values also appeared in steady-state PHCAP. Extxtim~ shows that three donor states are indelx~ent charge states. It seems that they are three DX-like centers originated fr~n different snuOx~ configurations. The eximmce of two or more DX-like centers is suggestedrecentlyin A1CraAs.1,2 1D. J. Chadi,Phys. Rev. B 46, 6777 (1992). 2Q. S, t-ham~ J. Y. Kang et al., J. Appl. Phys. 71, 5952 (1992);Phys. Rev. B 47, 13 215 0993).