Numerical Analysis on Polarization-Induced Doping III-Nitride n-i-p Solar Cells

作者：Lee Ya Ju^*; Yao Yung Chi; Yang Zu Po

来源：IEEE Photonics Journal, 2015, 7(1): 2300108.

DOI：10.1109/JPHOT.2015.2392374

• Polarization-induced doping
• III-nitride
• n-i-p solar cells
• wurtzite structure

We design and numerically evaluate a new type of III-nitride n-i-p solar cells whose p-and n-type regions with equal carrier concentration of 3 x 1018 cm(-3) are not generated by extrinsic impurity doping but by the so-called polarization-induced doping, which is induced by the graded InxGa(1-x)N layers of linearly increasing (from x = 0% to 30%) and decreasing (from x = 30% to 0%) indium composition to construct the conductive p-and n-type regions, respectively. Because of the identical and uniform polarization charges within each unit cell, a smooth spatial variation of the potential profile of the device is, hence, expected, which mitigates the energy band discontinuities at heterointerfaces and facilitates transportation and collection of photogenerated carriers with high efficiency. Most importantly, as the conductive n-and p-type regions are formed by electrostatic field ionization but not by the thermal activation, the concentration of field-induced carriers is independent of thermal freeze-out effects. Thus, the polarization-induced doping III-nitride n-i-p solar cells can provide stable power conversion efficiency, even when operated at low temperatures.

• 出版日期2015-2