A Study On The Characteristic Of Electroluminescence For GaN Based Lateral Structure Blue Light Emitting Diodes On Si Substrate

GaN compound semiconductors have attracted much attention because their large direct band gap have been demonstrated a large potential for applications in Optoelectronic devices. For all these applications, the III-V nitride layers are usually grown on sapphire or on silicon carbide substrates. The search for a substrate other than that for the fabrication of GaN LEDs has attracted much attention ever since the successful fabrication of GaN LEDs. The development of some of these applications on silicon substrates has obvious technological advantages, including the low cost, large-scale availability, good thermal and electrical conductivities and the feasibility of removing the Si substrates with wet etching. Significant mismatches in lattice constants and thermal expansion coefficients of silicon and GaN in growth process is existed, Such differences cause crack formation when the thickness of the grown film exceeds a critical thickness, which will bring in some questions about reliabilities of LED devices, and such material and related opto-electrical devices are still in the preliminary stage. Consequently, it is essential to study the reliabilities of blue GaN LED on Si substrate.The polarization fields in the InGaN/GaN MQWs, which result from the spontaneous and strain-induced piezoelectric polarization in this materials system, can weightily influence the optical and electronic properties of nitride materials. The polarization field of InGaN/GaN MQWs has been studied through various experimental and theoretical calculation methods which are very complicated and are not easy to operate. The polarization field in MQWs is estimated by the characteristic of electro-luminescence, as far as know, there is no reported in the world. Therefore, the investigation the EL characteristic of GaN LED on Si is of extreme practical importance.In this dissertation, some device properties of GaN LED on Si substrates are studied including: reliabilities, I-V characteristics, The EL properties and the polarization field of MQWs, The luminescence mechanism and so on. Some significant and innovative results is achieving as following:...