The BENDY LED (Light emitting diode) along with solar cells made up with inorganic compound semiconductor rods with graphene are achieving greater heights in technological advancement.

Presently, most versatile electronics and opto-electronic devices are made using organic materials. However, inorganic compound semiconductors (e.g. Gallium nitride (GaN)) have many advantages over the organic materials that include better optical, mechanical and electrical properties.

The major barrier that has so far restricted the use of inorganic compound semiconductors in such applications was the problem of growing them on flexible substrates.

Because of the variable colour light emission and high density integration properties, the GaN nano-structures and micro-structures are gathering attention amongst the research community.

These micro-structures when combined with graphene substrates show good tolerance for mechanical deformation.

Why to choose graphene for substrates?

Figure 1 – Micro-Rod Growth Process rendering.

Credits: Seoul National University

UItrathin graphene films contain weakly bonded layers of hexagonally set out carbon atoms supported by strong covalent bonds which makes graphene an ideal substrate. It provides required flexibility with good mechanical strength, it is chemically and physically stable at temperatures above 1,000°C.

Since, graphene has very stable and inactive surface, it offers small amount of nucleation sites for GaN growth. This would even boost the 3-D island growth of GaN micro rods on graphene.

A catalyst free metal organic chemical vapor deposition (MOCVD) process is used to create the actual GaN micro-structure LED’s on graphene substrates.

When the GaN micro rod LED’s were put under test to check their bendability and reliability on the graphene, it was found that the LEDs provided intense electroluminescence (EL) and were reliable. There was less degradation in optical performance after 1000 bending cycles.

This shows a big and better change for next generation electronic and opto electronic devices providing a large scale and low cost process.

With this advantage, flexible and reliable LED display can be used for commercial purpose.

Authors:

  1. Bunty B. Bommera
  2. Dakshata U. Kamble
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