Three-dimensional model for a standard HELLISH device. Schematic diagram to illustrate the quasi-flat band region (dotted lines) on the conduction and valence bands. Arrows depict the drifting and diffusion of the holes (white arrow) and electrons (black arrow). The non-filled arrow shows where the radiative recombination takes place, and the emitted photo energy is hν1.
Chaqmaqchee et al. Nanoscale Research Letters 2012 7:525 doi:10.1186/1556-276X-7-525