Thermionic escape of net photogenerated carriers and current densities from illuminated lightly doped single quantum wells

Photogenerated carriers captured in the intrinsic region of p/i/n GaAs–AlGaAs quantum well systems and contributing to current densities after thermionic escape, is the purpose of this communication. Illuminated intrinsic regions of solar cells with multiple quantum wells are expected to contribute an increase to overall collected currents when compared to bulk p/i/n solar cells. Carriers of the order of View the MathML source are found to be generated in single quantum wells of the i-region, and under 1017/cm2/s1 steady illumination flux levels (under Auger and radiative recombination mechanisms taken into account). Next, the contribution from each quantum well is evaluated in the form of thermionic current density values, and in terms of temperature and individual quasi-Fermi level position relative to the fundamental miniband in each well. Based on analytic results (for 30% Al fraction, and for 3–View the MathML sourcelightly doped GaAs layers), computations show that (a) current density may vary from 1 to View the MathML source quantum well, as a function of background doping level in the neighborhood of 1011–View the MathML source, and at three representative temperatures View the MathML source, 40°C (b) current density may vary from 0.1 to View the MathML source for a range of widths from 3 to View the MathML source, at the same temperatures, and for similar background doping (c) lightly doped View the MathML source GaAs quantum wells may generate current densities varying from 0.1 to View the MathML source under photo-carrier levels in the order of View the MathML source, and room temperature.