Integrated cooling for optoelectronic devices

Active refrigeration of optoelectronic components through the use of thin film solid state coolers based on III-V materials is proposed and investigated. Enhanced cooling power comparing to the thermoelectric effect of the bulk material is achieved through thermionic emission of hot electrons over a heterostructure barrier layer. It is shown that these heterostructures can be monolithically integrated with other devices made from similar materials. Experimental analysis of an InP p-i-n diode monolithically integrated with a heterostructure thermionic cooler is performed. Cooling performance is investigated for various device sizes and ambient temperatures. Several important non-ideal effects are determined such as contact resistance, heat generation in the wire bonds, and the finite thermal resistance of the substrate. These non-ideal effects are studied both experimentally and analytically, and the limitations induced on performance are considered. The experimental results are then used to predict the improved performance of better designed coolers. These micro-refrigerators can provide control over threshold current, power output, wavelength, and maximum operating temperature in diode lasers. Heterostructure integrated thermionic (HIT) cooling is demonstrated to provide cooling power densities of several 100’s W/cm.