Thursday, March 18, 2010

Iranian Researchers Improve Performance of Light Emitting Nanomaterials

The Iranian researchers managed to take a new step forward in the improving performance of transistors and light emitting sources' (LEDs and lasers), .

The researchers conducted their study with the aim of 'analyzing and evaluating the internal electric fields' effects on the performance of single and multiple quantum wells based on (GaN/InGaN) nanostructured nitrogen containing strain-balanced semiconductors'.

They derived electron and hole wave functions in a finite potential well of nanometric structures analytically by Schrodinger equation. Then they analyzed the quantum-confined Stark effect caused by internal piezoelectric field on the quantized energy levels' shifts which lower emitted light intensity and make a transition to red in quantum wells.

"Taking into account the dependency of effective mass of electric load carriers (electrons and holes) on nanostructure dimensions (quantum well widths in desired nanostructure) as an important factor in calculations" is one of the novel aspects of this research, Hamidreza Alayee, one of the research colleagues, said in an interview with the news service of the Iran Nanotechnology Initiative Council (INIC).

"Our calculations in the field of mechanical quantum were based on the theory of first and second order time-independent disturbance. We first evaluated carriers function waves in wells to find transition energy between basic states of electron and hole in quantum wells with different widths, then applied piezoelectric field potential as a disturbing factor in the model," Alayee added.

Noting that his co-researchers made the related calculations under two different conditions, he reiterated, "First, we assumed effective mass of carriers to be constant then we assumed it as a function of well width. The results showed that at the second conditions calculations fit the experimental data with an acceptable precision. These results revealed the accuracy of piezoelectric fields' presence and their influence on the mentioned structures as well."

The theoretical and experimental results of the present study could be applied in electronic and optoelectronic industries as well as designing and manufacturing parts like transistors and laser diodes.

The theoretical details of the present study are available at Physics Letters A., volume 374, pages 66-69, 2009.

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