The electrooptical properties of (100) and (111)B InGaAs/GaAs strained single quantum wells have been studied by the photoreflectance spectroscopy at various temperatures and under different biases. There is a Si delta-doping sheet under the GaAs surface to screen the surface built-in electric field from the quantum well. The spectral features consist of the excitonic interband transitions in the quantum well, and the Franz-Keldysh oscillations from the band edge transitions of the GaAs barrier near the surface. The piezoelectric field tilts the (111)B single quantum well toward the Si delta-doping and causes subband filling by the electrons from the delta-doping centers. With a proper external bias to repel electrons from the tilted quantum well, the excitonic interband transition in the (111)B system is enhanced.
|Number of pages||2|
|Journal||Japanese Journal of Applied Physics|
|State||Published - 2000|
- photoreflectance; strained single quantum wells; piezoelectric field; Franz-Keldysh oscillations