Monolithic integration of thin-film coolers with optoelectronic devices

Patrick Abraham John E. Bowers Department of Electrical and Computer Engineering University of California–Santa Barbara Santa Barbara, California 93106-9560 Abstract. Active refrigeration of optoelectronic components through the use of monolithically grown thin-film solid-state coolers based on III-V materials is proposed and investigated. Enhanced cooling power compared to the thermoelectric effect of the bulk material is achieved through thermionic emission of hot electrons over a heterostructure barrier layer. These heterostructures can be monolithically integrated with other devices made from similar materials. Experimental analysis of an InP pin diode monolithically integrated with a heterostructure thermionic cooler is performed. Cooling performance is investigated for various device sizes and ambient temperatures. Several important nonideal effects are determined, such as contact resistance, heat generation and conduction in the wire bonds, and the finite thermal resistance of the substrate. These nonideal effects are studied both experimentally and analytically, and the limitations induced on performance are considered. Heterostructure integrated thermionic cooling is demonstrated to provide cooling power densities of several hundred W/cm2. These microrefrigerators can provide control over threshold current, power output, wavelength, and maximum operating temperature in diode lasers. © 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)02511-3]