چكيده به لاتين
light emitting diodes consist of an electron transfer layer and a hole transfer layer. Electrons and holes pass through these transfer regions to the middle region called the active region, and by recombining in this region, they radiate light. In the structure used in this research, the active region consists of a quantum well. In this dissertation, first the various processes in this type of device are explained and then, while examining the features and specifications of GaAs/AlGaAs based semiconductors and light emitting diodes, the importance and application of such light emitting diodes are stated. In this research, a GaAs/AlGaAs based light emitting diode with a wavelength of 660 nm is designed and characteristics such as conduction threshold voltage, power spectral density, emitted wavelength range and radiative power are studied. Numerous factors affect the performance of light emitting diodes, so the effect of quantum well thickness, layer density, temperature and bias voltage on the characteristics of light emitting diodes has been investigated. Then new structures of light emitting diodes with stepped quantum wells and stepped quantum barriers are expressed. In the new design, with the changes that take place in the shape of the well and the potential dam, the spectral density and radiative power of the part increase. Then, the optimal structure, which is a combination of a three-stage quantum well and a three-stage quantum dam, is expressed. The proposed power spectral density structure is 28% relative to the three-stage quantum dam structure and 12.5% relative to the three-stage quantum well structure increases. Also, the amount of radiation power of the proposed structure increases by 17% and 10%, respectively, compared to the structure of a three-stage quantum dam and a three-stage quantum well. Finally, in order to improve the performance of light emitting diodes the structure based on GaAs/AlGaAs, AlGaAs/AlGaAs, AlAs/AlGaAs distributed Brag reflective layers is investigated. The spectral power density and radiative power of light emitting diodes based on n-p-AlGaAs/AlGaAs DBR distributed Brag reflector layers are improved by 15% and 21% compared to the n-AlGaAs/AlGaAs DBR structure and Reference structure, respectively. All checks were performed using Silvaco TCAD software.
