Little is known about the "low energy" emission ( h ? < E -E ) from p-GaAs.c v In the present work we report about the trlow energy" bands at hS = 0.93 and 1.02 eV in p-GaAs and compare them with similar bands in n-GaAs.

Investigations of the low energy emission bands a t 0.93 to 1.0 eV in Te-doped n-type GaAs were made. An analysis is given of the dependences of steady state photolumineseence intensity and the kinetics of the photoluminescence decay on temperature and exciting light intensity and this leads to a scheme of electron transitions via radiative centres with the following parameter values: energy position ( E , + 0.5 eV), concentration ( N = 1015 to 10l6 ~m -~) , electron and hole capture coefficients (y,, = 5 x cm3 s-l, yp = 2 : < x HponeReHo m y q e~~e I I H~K O~H~~~~T~. I Y~C K M X ~O J I O C ~a n y s e~~n 0,93 go I ,O 3B om3 s-l a t T = 77 to 400 O K ) . I3 n-GaAs, JIerMpOBaHHOM Te. A~anrna 3aBHCEiMOCTefi HHTeHCHBHOCTH CTaUMOHap-H O f i @OTOJIIoMHHeCL[eHUHkI H HHHeTHIEM 3aTyXaHMH @OTOJIIOMI~HeCUeHUHH OT T6M-nepaTypbI H YPOBHH ~036ymge~mn ~O~B O~I H J I onpenenmb cxeniy ~J I~K T P O H I I~I X rIepexoaoB vepea 113nysalou~e UeHTpbI II IIX xapaIwepncTmai : a~e p r e~~s e c~o e IIOaOmeHHe ( E , + 0,5 3 R ) , KOHIJeHTpaUHIO ( x = loi5 a0 10" CM-3), K03@$HUHeHTbI 3aXBaTa 3JIeKTpOHOB H EbIPOK (Yn = 5 X CM3 Ce1E-I npH T = 77 AO 400 O H ) . CM3 CeH-' , yp = 2 X

Heat treatment of n‐GaAs leads to a disappearance near its surface of the 0.93 eV emission band and to an appearance of the 1.0 and 1.28 eV emission bands. In the GaAs interior the 1.0 eV emission band gradually shifts to lower energies (0.93 eV), only weakly changing its intensity, the intensity of the 1.28 eV emission band monotonically decreases. The shift of the 1.0 eV emission band is the result of a superposition of the 1.0 and 0.93 eV emission bands with different intensities: the 1.0 eV emission band is at maximum and the 0.93 eV emission band at minimum near GaAs surface, and the 1.0 eV emission band is at minimum and the 0.93 eV emission band at maximum in the GaAs interior. Evidence is presented that in n‐GaAs the 0.93 eV radiative centres may be associated with the VGaVAs divacancy, and the 1.0 eV radiative centres, with substitutional copper atom–vacancy pairs (CuGaVAs). The 1.0 eV radiative centres are formed by filling a VGaVAs divacancy (the 0.93 eV radiative centre) by diffusing copper atoms; this explains the 1:1 correspondence between changes in the intensities of the 1.0 and 0.93 eV emission bands.

No abstract

It is shown that the introduction of copper atoms into GaAs crystals containing antistructure d e fects EL2 (isolated arsenic atoms on gallium sites AsG~) leads to a practically complete disappearance of the ELZinduced luminescence bands peaked at 0.63 and 0.68eV. This effect is connected with the passivation of the EL2 defects (i.e. with the substantial decrease in their concentration) because of their interaction with copper atoms (they become bound by copper atoms) resulting in an appearance of electrically inactive A S G~C U G~ complexes.