Browsing by Author "Shen, TL"

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Electroreflectance of surface-intrinsic- n(+)-type doped GaAs
(1997-09-15)
Wang, DP
;
Huang, KM
;
Shen, TL
;
Huang, KF
;
Huang, TC
The electroreflectance spectra of surface-intrinsic-n(+)-type-doped GaAs were measured at various bias voltages (V-bias). Results revealed many Franz-Keldysh oscillations (FKOs) above the band-gap energy, which have been attributed to a uniform electric field (F) in the undoped layer below the surface. However, there has been no other evidence for the uniformity of F in the undoped layer. Since it is known that F can be deduced from the periods of the FKOs, the relations between F and V-bias can, thereby, be obtained. The nearly linear relation, thus found, confirms the existence of a nearly uniform field in the undoped layer. From the plot of F against V-bias,the Values of the thickness of the undoped layer and the barrier height can also be evaluated. (C) 1997 American Institute of Physics.
Electroreflectance of surface-intrinsic- n(+)-type doped GaAs
(1997-09-15)
Wang, DP
;
Huang, KM
;
Shen, TL
;
Huang, KF
;
Huang, TC
The electroreflectance spectra of surface-intrinsic-n(+)-type-doped GaAs were measured at various bias voltages (V-bias). Results revealed many Franz-Keldysh oscillations (FKOs) above the band-gap energy, which have been attributed to a uniform electric field (F) in the undoped layer below the surface. However, there has been no other evidence for the uniformity of F in the undoped layer. Since it is known that F can be deduced from the periods of the FKOs, the relations between F and V-bias can, thereby, be obtained. The nearly linear relation, thus found, confirms the existence of a nearly uniform field in the undoped layer. From the plot of F against V-bias,the Values of the thickness of the undoped layer and the barrier height can also be evaluated. (C) 1997 American Institute of Physics.
The effects of the magnitude of the modulation field on electroreflectance spectroscopy of undoped-n(+) type doped GaAs
(1998-01-01)
Wang, DP
;
Huang, KM
;
Shen, TL
;
Huang, KF
;
Huang, TC
The electroreflectance (ER) spectra of an undoped-n(+) type doped GaAs has been measured at various amplitudes of modulating fields (delta F). Many Franz-Keldysh oscillations were observed above the band gap energy, thus enabling the electric field (F) in the undoped layer to be determined. The F is obtained by applying fast Fourier transformation to the ER spectra. When delta F is small, the power spectrum can be clearly resolved into two peaks, which corresponds to heavy- and light-hole transitions. When delta F is less than similar to 1/8 of the built-in field (F(bi)similar to 77 420 V/cm), the F deduced from the ER is almost independent of delta F. However, when larger than this, F is increased with delta F. Also, when delta F is increased to larger than similar to 1/8 of F-bi, a shoulder appears on the right side of the heavy-hole peak of the power spectrum. The separation between the main peak and the shoulder of the heavy-hole peak becomes wider as delta F becomes larger. (C) 1998 American Institute of Physics.