The deposition of uniform arrays of CdTe/CdS heterostructures suitable for solar cells via close-spaced sublimation is presented. The approach used to create the arrays consists of two basic steps: the deposition of a patterned growth mask on CdS, and the selective-area deposition of CdTe. CdTe grains grow selectively on the CdS but not on the SiO 2 due to the differential surface mobility between the two surfaces. Furthermore, the CdTe mesas mimic the size and shape of the window opening in the SiO 2 . Measurements of the current density in the CdTe were high at 28 mA/cm 2 . To our knowledge, this is the highest reported current density for these devices. This implies that either the quantum efficiency is very high or the electrons generated throughout the CdTe are being concentrated by the patterned structure analogous to solar concentration. The enhancement in crystal uniformity and the relatively unexplored current concentration phenomenon could lead to significant performance improvements.

Cadmium telluride (CdTe) is a good absorber layer for solar cells with a predicted efficiency of 29% however the highest reported efficiency is only <17% due to various loss mechanisms. One particular loss is attributed to nonuniformity in grain shape and size by Karpov. Simulation of Karpov's model yields counter-intuitive insight that highlights how empirical data can lead researchers to wrong conclusions. A method to grow ordered arrays of ZnTe/CdTe heterostructures is presented. The method has potential for probing the electronic characteristics of individual photodiodes at the granular level.