Cadmium-hydrogen shallow acceptor complexes in germanium

Vol. 93, No. 5 donor level crossings (magnetic degeneracy) due to the anisotropy of the effective mass. This fact must give rise to proper electric dipole moment of t h e e x c i t e d neutral impurity [at 9.9 T a n d at 3 5 . 5 T for Si] and consequently to anomalous impurity polariz a t i o n a n d to n e w r e s o n a n c e s in elastic scattering since the long-range carrier-donor interaction arises. The spectral problem is solved in the framework of effective mass approximation and the variational method for the appropriate Sr~dinger equation solution is u s e d . Our choice for trial wave function is b a s e d on t h e m a x i m u m a c c o u n t of their asymptotic and symmetric properties. Found solutions can be used for matrix element calculations particularly for the calculation of the impurity dipole moment and for finding impurity potential which determines free charge carrier scattering. W e a l s o p r e d i c t the possible non-elastic resonances

Cadmium-Hydrogen sbanaw Accepter Complexes in Germanium L. HSu', E. E. Hailer'. W. Pf©fffezt. A. Bureha.,d~',b',.. Dcichc=t, R. Ma~.rlet and M. Zacater "Lawrence Berkeley Laboratory and University of California, Berkeley, CA 94720, tFakult~t ~ Phy$ik. UniversiMt Eon~tanz. D.78434 lf on.tta~. , FRG. We have observed a new shallow aceeptor in germanium which wc attribute to a cadmium-hydrogen singic acceptor complex, analogous to beryllium¢11.1.2 hydrogen, zinc-hydrogen, and coppor-dthydrog The radioisotopea ll~'Cd and "*In wcm implanted in several high purity n-type Ge w~CZ~. The uenptcs were then annealed and hydrogen was added. Hall effect mcasurcmnnts .~)owe,d thai the implanted region was ptype. Pcnud~l Angular Correlation Spectroscopy ('PAC$) indicated the presence of In/Cd-H pairs. Photothcrmal ionization spectroscopy (PTI$) was used tO identify hydrOgcnic l¢¢,e1~o¢ levels. AS cars be seen below, PTIS on one sample, annealed at 80OK. reveals the prcscnce of shallow sccelXor kvels that do not cormsl:xmd to any known impurity or impurity complex and which were not present in the original wafer. We atl.~.butc the new spc,:tmm m a Cd-H shallow zcceptor complex. The visible D. C, and B lines lead to a ilround state energy of ~ =,17.7 mcV. A lrfl$ ~ of the Ce-H~ "=_':__'~;*~,~ is included below I0 ShOw thatwhim the binding ener~ of this amter is c l c ~ to that of Cd-H, the two can be d;qin~Nisbcd, as seen by the i)caks on the low ~crgy side or"Ihe C4-H D and C lines.

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ABSTRACTS 1. R.E. McMun'ay, Jr., N. 51. Haegcl. J. M. Kahn and

E. E. Hailer, Solid State Commun. 61,2.7 (1987). 2. J. M. Kahn, !;. E. Halter and L. M. Falicov, "Prnc. 18th ICP$" ed. O. Engstrom, Worm Scientific (1987). Thi.s wCzk wz¢ SUPlX~'teclby the U.S. National Science Foundation under Contract No. DMR-91 15856.

PHOTOLUMINESCENCE STUDY OF SHALLOW IMPURITIES LOCALIZATION IN TRANSMUTATION DOPED GaAs V.A. Bykovsky, V.[. Khit'ko, V.F. Shoh and V.[. Utenko Recearch Institute of RadiomateFials, Kizhevatova 86, 220115 Minsk, Belarus The accepter Localization o£ shallow transmutaLed ialpu[itles (Ge, gn), compiexation of mesidual impurities (C, Si) and cadiation induced de£ects, mechanisms oK radiative recombination in epitaxial layers and bulk GaAs crystals doped by the neutEon transmutation (ND) and photo nuclear reaction (PND) methods were investigated by low temperature (T= 4.2 K) photoluminescenee (PL). The accepter localization of transmuted Ge atoms is stable in the course of annealing up to T=550°C ~ r w~akly NTD epitaxial layers (n< 5*lO--cm -).The intensities oK PL bands due conduction band-accept or, donor-accepter pair transit4ions with participation of Ge accepters are comparable with that for residual accepters (C, 8i) in starting material. The intensive PL bands of transomted Zn accepters were found in PND epitaxial layers, but Ge accepter band is extremely weakly. After annealing at 400-600"C for slightly NTD bulk GaAs ( n< 5"i016cm -3) the main P5 band is due Ge transmuted accepters. But after high temperature annealing (T> 700°C) the intensities of PL bands of C,Si residual accepters are restored and Ge accepter PL band is weakly. Such behaviour is attributed to the formation and breakdown nonradiative recombination centres including the residual accepters (C, Si) and radiation induced defects. The new zero phonon lines with participation of shallow amphoteric impurities (Ge, Si) and transition metals (Cr, Fe) were found. The model of centres includiing shallow accepters of IV group in As sites and interstitial atoms of transition metals is discussed.

H y d r o g e n P a s s i v a t e d D e f e c t s in InP

C. P. Ewels I, S. Oberg 2, P. R. Briddon 3, J. Goss I, R. Jones I, S. J. Breuer 3, R. Darwich 4 and B. Pajot 4 Ab mitio local density functional cluster calculations are carried out on hydrogen passivated B e and Z n acceptors and on a hydrogen-iron complex as well as the fully