Effect Of InGaN/GaN Quantum Well Of GaN-based LED

Currently research of light-emitting devices, the most commonly used compound semiconductor materials is the wide bandgap nitrides semiconductor materials, one of the most representative is a gallium nitride. However, it is difficult to prepare the gallium nitride bulk single crystal, and the epitaxy has been developed in industry by using MOCVD on the different substrates, such as sapphire, silicon carbide and silicon. For the vertical structure light-emitting diode, the most ideal material used substrate is SiC because of the semi-conductor property. As the silicon carbide substrate is a semiconductor material, to weld N electrode, we should weld N electrode directly on the silicon carbide substrates. Not as the sapphire substrate is an insulating material we should etch the epitaxial film from P-type gallium nitride to N-type gallium nitride material for weld N electrode. In order to this structure applied to practical production preferably, we done simulation research to the vertical structure of SiC substrate GaN-based multiple quantum well LED, we build two dimensional silicon carbide substrate GaN-based multiple quantum well structure light-emitting diode model by the semiconductor device simulate software which is named as the Sentaurus TCAD. The GaN/InGaN LEDs have a vertical pattern with P and N electrodes on the vertical at 80 mA injection current. We simulated the properties of GaN/InGaN LEDs by changing the In component in wells and width of wells and barriers, respectively. Then, we analyzed current voltage(IV) characteristic and external quantum efficiency,and discussed the spontaneous emission spectral intensity and red shift phenomena. The main works of this paper as follows:The change In content between 0.1 to 0.3 in different experimental model, we found that the current voltage(IV) characteristic of the device was optimized with increase In content, and the spectrum appears red shift and luminous intensity is drop with the increase of In content, external quantum efficiency and decreases with increase In content.When the quantum well width always unchanged, the optical properties to the device is in one of the main influence near the well or barrier of P-type whether well or barrier change. For the width of different barrier and well, InGaN/GaN multiple quantum well LED current voltage characteristic is different with well or barrier change of near the P-type is slightly different. When keep the quantum well width change always, when well width form 2 to 3 nm change, more smaller well width make to optimize the performance of LED. The width barrier form 8 to 12 nm change, with the increase of barrier width, the performance of device could be optimized. Through the comprehensive comparison found that well influence on device can much bigger than the influence of the barrier.From the simulation results, we can change any of the three parameters to obtain the optimization design according to the different application requirements of LED in the actual production. When designing the device performance too bad to our imagine requirements, the performance of adjustment change well or In content to improve the actual device, when the deviation is small, we adjust the barrier width to improve the performance of the device. We should take care of both the voltage characteristics and optical properties in the device design to achieve optimal InGaN/GaN multiple quantum well LED device.