Optical activity of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>EL</mml:mi><mml:mn>2</mml:mn><mml:mn /></mml:math>metastable state under hydrostatic pressure

Baj, M.; Dreszer, P.

doi:10.1103/physrevb.39.10470

Cited by 30 publications

(9 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus it remains the third possibility that the effect is caused by a change of a charge state of the metastable configuration due to trapping of the photoexcited electron. Such explanation is in agreement with recent findings of Baj et al [13] who showed that EL2 in the metastable configuration is an electron trap.…”

supporting

confidence: 82%

Light Induced Recovery of EL2 Defect from the Metastable Configuration

Teisseyre

Kuszko

1991

Acta Phys. Pol. A

View full text Add to dashboard Cite

The measurements : of changes in a magnitude of ΕL2 characteristic infrared absorption were used to investigate a phenomenon of light induced recovery of the defect from its metastable state in semi-insulating (SI) and n-type GaAs. At a temperature of 12K illumination with photons of energy 1.45 eV caused partial recovery for both SI and n-type samples. For n-type samples partial recovery occurred also after irradiation with photons of energy lower than 0.73 eV.PACS numbers: 71.55.Eq, 78.50.GeDuring recent decade EL2 defect in GaAs has been one of the most intensely investigated defects in semiconductors. The presence of an optically induced metastable configuration is the most puzzling feature of this defect. The metastable state is reached when a cooled sample is illuminated with photons in the range of 1-1.3 eV [1]. For some time it has been commonly accepted that the only way for the EL2 to return from metastable to ground state configuration is thermal recovery occuring when the sample is heated to approximately 40 K for n-type and 120 K for SI type of GaAs. Recently, it has been reported by several authors that the recovery process can also be induced by illumination of a sample with photons in the range of 0.7-1.5 eV. In the Table a summary of these data is reproduced alter Manasreh et al. [2].There are considerable discrepancies in the magnitude of the elect observed by different authors. It is not clear whether these discrepancies are due to a different method of detection, experimental conditions or a sample used. Most of the results were obtained at liquid nitrogen temperature which is considerably higher than the temperature at which the recovery process occurs at presence of free electrons in n-type sample. At 77 K light induced recovery of EL2 in SI sample may *This work was supported by CPBP 01.05.(267)

show abstract

supporting

confidence: 82%

Light Induced Recovery of EL2 Defect from the Metastable Configuration

Teisseyre

Kuszko

1991

Acta Phys. Pol. A

View full text Add to dashboard Cite

show abstract

“…the acceptor-like ( E L 2 * )°/ -l e v e l e n t e r s t h e e n e r g y g a p u n d e r p r e s s u r e . W e p r o p o s e t h a t i n n -G a A s t h e ΕL2 thermal recovery takes always place via the (ΕL2') state.PACS numbers:71.55.Eq, 78.50.GeOur recent experimental results showed that under pressure of p > 0.3 GPa the metastable configuration of the EL2 defect in GaAs became optically sensitive and a very efficient pure optical recovery process was observed [1]. We suggested that these facts could be related to the acceptor-like level of the metastable EL2 -(EL2*)0/ -, entering the gap under pressure.…”

mentioning

confidence: 93%

“…Our recent experimental results showed that under pressure of p > 0.3 GPa the metastable configuration of the EL2 defect in GaAs became optically sensitive and a very efficient pure optical recovery process was observed [1]. We suggested that these facts could be related to the acceptor-like level of the metastable EL2 -(EL2*)0/ -, entering the gap under pressure.…”

mentioning

confidence: 97%

Acceptor-Like Level of the EL2 Defect in its Metastable Configuration

1991

View full text Add to dashboard Cite

This paper presents for the first time the evident experimental confirmation that ΕL2 defect, while being in its metastable configuration, traps under hydrostatic pressure an additional electron, i.e. the acceptor-like ( E L 2 * )°/ -l e v e l e n t e r s t h e e n e r g y g a p u n d e r p r e s s u r e . W e p r o p o s e t h a t i n n -G a A s t h e ΕL2 thermal recovery takes always place via the (ΕL2') state.PACS numbers:71.55.Eq, 78.50.GeOur recent experimental results showed that under pressure of p > 0.3 GPa the metastable configuration of the EL2 defect in GaAs became optically sensitive and a very efficient pure optical recovery process was observed [1]. We suggested that these facts could be related to the acceptor-like level of the metastable EL2 -(EL2*)0/ -, entering the gap under pressure. In this work we present the experimental evidence of the above suggestion. We investigated two n-GaAs samples: #5Β with n300Κ = 1.2 x 1016 cm-3, ΝEL2 = 2.7 x 101 6 c m -3 a n d # 1 5 C w i t h n300κ = 3.2 x 10 16 cm-3 , ΝΕL2 = 1.3 x 1016 cm-3. Clear manifestation of the (EL2*)°/ -level was observed in electrical (conductivity and DLTS) measurements.At temperatures Τ < Τ (where Τ -temperature at which EL2 thermally recovers) and sufficiently high pressure (p > 0.3 GPa) during subsequent optical quenching and optical recovery processes strong persistent changes of the electrical conductivity were observed. This was the consequence of the trapping and releasing of the electrons by EL2 optically transferred between its normal (EL20) and This worlds supported by CPBP 01.05 Program of the Polish Ministry of National Education (129)

show abstract

“…Some of excited electrons were captured by shallow donors which was directly shown by a magnetooptical experiment [4]. A long lifetime of optically excited electrons in the conduction band and on shallow donors is caused by a configurational barrier for capturing an electron on the EL2 [5] and a spatial separation of an excited electron from its parental centre [6]. A sufficiently high electric field caused impact ionization of electrons bound on shallow donors and in wells of the fluctuating potential at the bottom of the conduction band.…”

Section: Introductionmentioning

confidence: 99%

Non-Activated Conductivity of Hot Electrons in Localization Regime

Łuskowski

Grynberg

1995

Acta Phys. Pol. A

View full text Add to dashboard Cite

Temperature (Τ) dependence of conductivity (σ) was studied in semi--insulating GaAs as a function of the magnetic field (B) for 1.8 K< Τ < 40 K for high electric fields. An infrared illumination of a sample and application of an electric field caused a non-equilibrium distribution of electrons in the conduction band. An increase in B caused a localization transition which manifested itself by a gradual disappearance of the impact ionization of shallow bound states. The transition was connected with a change from a non-activated to an activated conductivity only if Τ > 4 K, otherwise σ showed only a non-activated character. It is proposed that for Τ < 4 K the electron distribution function is mostly determined by optical and electric field excitations, which results in a non-activated conductivity. For T> 4 K thermal excitations become dominant which leads to an activated character of σ.

show abstract

Optical activity of theEL2metastable state under hydrostatic pressure

Cited by 30 publications

References 17 publications

Light Induced Recovery of EL2 Defect from the Metastable Configuration

Light Induced Recovery of EL2 Defect from the Metastable Configuration

Acceptor-Like Level of the EL2 Defect in its Metastable Configuration

Non-Activated Conductivity of Hot Electrons in Localization Regime

Contact Info

Product

Resources

About