Characterization of Quantum Well Infrared Photodetectors by Analysis of Noise Spectral Density

Download or read book Characterization of Quantum Well Infrared Photodetectors by Analysis of Noise Spectral Density written by Lisa Kore and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Three quantum well infrared photodetectors are characterized utilizing noise spectral density and current-voltage measurements taken at a variety of temperatures and biases. Though all devices were fabricated using the GaAs/InGaAs material system, each has a unique morphology. D1 had three different quantum wells per period and 20 periods. D2 had one type of quantum well and 10 periods. D3 had one type of quantum well, 5 periods, and asymmetric barriers. Measurement temperatures for D1 ranged between 80 K and 180 K with bias values for each temperature between zero and 35 mA. For D2 and D3 measurement temperatures ranged between 80 K and 125 K with bias values for each temperature between zero and 10 mA. Utilizing models for thermionic emission current and Fowler-Nordheim tunneling current the current-voltage characteristic of each device was compared with the theory. The thermionic emission model did well for all devices at low bias. The tunneling model did well for all devices at high bias. In the middle range of biases D1 was underestimated by the models, D3 was overestimated by the models, and D2 was modeled well by a sum of the two models.