The electron–hole overlap in the parabolic quantum well light emitting diode is much superior to the rectangular: even to that of a staggered quantum well
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The strong piezoelectric field in the InxGa1−xN/GaN quantum well (QW) LEDs, separates the electrons and holes spatially, which decreases the luminescence. Various shapes and compositions of such QWs are studied to improve the performance. We have studied the transition energy (TE), overlap of electron and hole wave functions, band structures and field distributions of the parabolic QWs (PQW) through the self consistent solutions of Schrödinger and Poisson equations. The shape of the PQW is varied along with the compositions and dopings. The square of the overlap of electron and hole wave functions i.e. the transition probability (TP) is strikingly increased, compared to the rectangular QW and it is even higher than the symmetrically staggered QW. At a particular current density, for the same TE, the TP of the PQW increases more than two times that of the rectangular QWs. An important feature, desirable for the QW LEDs emerge. The change of the TE with increase in the current density is minimized. A brief theory, computational procedures and the results will be presented in details with suitable discussions.
KeywordsInGaN/GaN parabolic QWs Light emitting diodes Transition energy Transition probability J–V characteristics
We would like to thank Dr. Siddhartha Panda, of this laboratory (Microwave and Solid State Electronics Laboratory, Institute of Radio physics and Electronics) for valuable discussions and illuminating suggestions. A. Mistry would like to thank the University Grants Commission, India, for financial support under the RGNF scheme. A. Gorai would also like to thank the University of Calcutta, India, for financial support under the Payodhinath Mukherjee research fellowship. The funding was provided by University Grants Commission (Grant No. F1-17.1/2014-15/RGNF-2014-15-SC-WES-67948), University of Calcutta (Grant No. ET/T/67).
- Dreyer, C.E., Janotti, A., Van de Walle, C.G., Vanderbilt, D.: Correct implementation of polarization constants in wurtzite Materials and Impact on III-nitrides. Phys. Rev. X 6, 021038 (2016)Google Scholar
- Morkoc, H.: Handbook of Nitride Semiconductors and Devices, vol. 1, 2, 3. Wiley-VCH, Weinheim (2009)Google Scholar
- Singh, J.: Physics of Semiconductors and Their Heterostructures. McGraw-Hill, New York (1993)Google Scholar