Electric-field dependence of electroreflectance and photocurrent spectra at visible wavelengths in MOVPE-grown InAlGaP multiple strained quantum-well structures.

摘要

The authors present electric-field dependent electroreflectance and photocurrent spectra of visible-bandgap In(sub x)(Al(sub y)Ga(sub 1(minus)y))(sub 1(minus)x)P/In(sub x(prime))(Al(sub y(prime))Ga(sub 1(minus)y(prime)))(sub 1(minus)x(prime))P multiple-quantum-well (MQW) structures. These structures, grown by metal-organic vapor phase epitaxy on 6(degrees)-misoriented (100) GaAs substrates, have undoped MQWs sandwiched between doped In(sub 0.5)Al(sub 0.5)P layers, forming p-i-n diodes. Quantum-well compositions in the range 0.46 = or < x = or < 0.52 and 0(le)y(le)0.4, corresponding to bandgaps in the red to yellow-green range, were used. The Stark shifts in these various samples were measured and found to depend on the details of the Mg p-type doping profile, confirming important diffusion effects, in agreement with secondary ion mass spectrometry and capacitance-voltage data. The results show that these new materials are promising for visible-wavelength optical modulator applications.