A new infrared detector

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Texas Tech University

A theoretical and experimental program to determine the feasibility of various semiconductor systems for use as infrared quantum counters (IRQC) has been developed. A particular system, GaP:ZnO, was studied. The theoretical study consisted of calculating the efficiency (~60%), the detectivity (1.54 X 106 W-1) and other pertinent parameters as outlined in the appendixes. This study showed that theoretically the prospects of using this type of an impurity system for an IRQC were favorable. The preliminary theoretical study was followed by actual testing of the IRQC to determine agreement with predicted operation. The coincidental irradiation of the sample with infrared and pump signal produced an enhancement of flourescence, thus verifying the principle. Our data demonstrates that the ZnO level in GaP shows the possibility of being a very sensitive and efficient infrared (IR) detector to a broad band of IR (near IR to 20 microns), with a rise of less than 100 nsec. The inherent properties of IRQC's indicate low noise levels are possible in these types of detectors, making GaP:ZnO and other similar systems very attractive candidates for further investigation. There is a definite possibility of exceeding present state-of-the-art device characteristics with further experimentation. The experimental verification resulted in the development of a unique laser spectroscopy facility, incorporating both visible and far infrared lasers. The available dye laser is tunable from the blue to the near infrared by selecting the proper dye. The IR lines available range from the near IR to far IR. This facility will allow for the further study of IRQC systems and other related recombination processes that are at present not well understood.

Infrared detectors