Arif Muhammad , pp. 66. ING/School of Engineering, 2012.
Semiconductor materials, due to their high performance capabilities, are widely used in electronic and optoelectronic devices. The properties of band gap play a significant role in characteristics of semiconductor materials. Electrical properties of semiconductor materials are greatly affected by variations in their band structures. Impurities are added to semiconductor materials to get the desired properties. Semiconductor materials have several types of defects (shallow defects and Deep Level Defects) which influence their properties, which in-turns affect the efficiency of the electronic devices.
Gallium Nitride (GaN) and its ternary alloy Aluminum Gallium Nitride (AlGaN), are used for fabrication of electronic and optoelectronic devices. They can be affected by several defects which need to be characterized, to use the material in more efficient way. Shallow defects are frequently reported and explained theoretically; but the Deep Level Defects (DLDs) are rarely reported and therefore our study is focused on finding and characterizing the Deep Level Defects.
In this study, the electrical and optical properties of several semiconductor materials are experimentally tested using Deep Level Transient Spectroscopy (DLTS) Technique, and the results are presented for n-type AlxGa1-xN, with different Aluminum (Al) mole fractions as, x = 0.0, 0.14 and 0.20. As we increase the Al mole fraction, the electron traps moves deeper into the energy band gap. Some types of DLDs were found, which were never reported before.