Study of semiconductor quantum dots and their applications are of technological importance. Due to size quantization, some unique phenomena like enhancement in band gap, creation of crystal defects, etc. occur in the specimen. These properties make them very attractive for developing nano electronics, optoelectronic and optical devices. Modifications of these properties can be obtained on irradiation of the samples with swift heavy ion (SHI). This book describes about the synthesis of semiconductor quantum dots, cgharacterizations as well as their applications in electronics and optics.