Growth and realization of InGaAs/InP and InGaAs/InGaAsP quantum photonic devices grown by chemical beam epitaxy

The demonstrated capability of chemical beam epitaxy in producing high quality Ill-V materials while preserving the interface abruptness makes this growth technique particularly suited to the realization of that classes of devices in which the interface control is required to the highest extent. In this paper we will first present our results on Wannier Stark modulators exploiting InGaAs/InP short period superlattices. The understanding of the influence of the growth parameters enabled the growth and the fabrication of devices in waveguided configuration showing transmittance on-off ratio higher than 20 dB at working wavength of 1550 nm with bias voltages lower than 3 V. Transmittance and photocurrent studies on those devices enabled to determine electron wavefunction coherence length of at least seven SPSL periods at room temperature thus confirming the high quality of this material even in this dimensionality regime. Chemical Beam Epitaxy is also a suitable technique for the growth of bulk materials and quantum wells in the InGaAsP system. Along with the presentation of data concerning bulk quaternary layers in the whole compositional range of interest (from InP to InGaAs) we will discuss also HRXRD spectra of quantum wells structures exhibiting diffraction orders from -10 to +7 and low temperature photoluminescence data (FWHM=4.5 meV) confirming the high quality of the grown devices. The use of this material enabled the fabbrication of waguide electro-absorption modulators achieving (for the first time) polarization-insensitive operations without the need of strained active layers or parabolic QW structures. Also in this case high on-off contrast ratios (20 dB at 2.0 V and 30 dB at 5.5 V reverse bias) were achieved. These results were possible using large and shallow OW based on unstrained quaternary materials. Insertion losses as low as 2 de are measured. Within 2 dB and up to -6.5 V, all the attenuation and contrast figures are the same for TE and TM modes, being wavelength-independent in the wavelength range 1.55-1.58 mm. The growth of high resistivity InP: Fe doped with resistivities as high as 10(8) Omega/cm and excellent morphological and structural properties will also be discussed.