Stark Effect Suppression in (In,Ga)N Nanoheterostructures

Stark Effect Suppression in (In,Ga)N Nanoheterostructures
Purdue MSE, CGT, and ECE researchers have demonstrated geometries that suppress the pyroelectric and piezoelectric-induced Stark Effect from nanorods for (In,Ga)N-based light-emitting diodes. By controlling the aspect ratio of the deposited layers, their deleterious effects on optoelectronic performance can be mitigated.

(In,Ga)N nanostructures show great promise as the next generation LED technology. Its main advantage resides in the possibility of directly converting electrical energy into light without the use of down-converting phosphors. One of the most important challenges to realize the potential of this technology is to relax the high level of built-in electric field induced by the spontaneous and piezoelectric polarizations. Here, a research team that includes graduate students Zhiwen Liang, Isaac H. Wildeson, Robert Colby, and David A. Ewoldt, and Tong Zhang, as well as Professors Eric A. Stach, Timothy D. Sands, Bedrich Benes, and R. Edwin Garcia, has analyzed the benefits of Nanorods with pyramidal semipolar-oriented caps to supress the built-in electric field. Three-dimensional calculations performed on this structure demonstrate an order of magnitude reduction in electric fields, compared to the corresponding (traditional) thin film configuration. 

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