There has been tremendous progress lately in the field of III-nitride (GaN, AlN, InN) semiconductors and their device applications. For example, the invention of III-nitride-based blue laser diodes was the key to a new high-density data storage technology, the Blue-ray disc. Concurrently, improvements in III-nitride-based solid state light sources have led to their use in an increasing number of illumination applications, moving steadily toward the goal of general lighting. This book focuses on three emerging areas for III-nitride applications - chemical and biological sensing, energy...