By Topic

Heterojunction blocking contacts in MOCVD grown Hg1-xCd xTe long wavelength infrared photoconductors

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)
Musca, C.A. ; Dept. of Electr. & Electron. Eng., Western Australia Univ., Nedlands, WA, Australia ; Siliquini, J.F. ; Nener, B.D. ; Faraone, L.

The theoretical and experimental performance of Hg1-xCd xTe long wavelength infrared (LWIR) photoconductors fabricated on two-layer heterostructures grown by in situ MOCVD has been studied. It is shown that heterojunction blocking contact (HBC) photoconductors, consisting of wider bandgap Hg1-xCdx Te on an LWIR absorbing layer, give improved responsivity, particularly at higher applied bias, when compared with two-layer photoconductors incorporating n+/n contacts. An extension to existing device models is presented, which takes into account the recombination rate at the heterointerface and separates it from that occurring at both the contact-metal/semiconductor and passivant/semiconductor interfaces. The model requires a numerical solution to the continuity equation, and allows the device responsivity to be calculated as a function of applied electric field. Model predictions indicate that a change in bandgap across the heterointerface corresponding to a compositional change of Δx⩾0.04 essentially eliminates the onset of responsivity saturation due to minority carrier sweepout at high applied bias. Experimental results are presented for frontside-illuminated n-type Hg1-xCdxTe photoconductive detectors with either n+/n contacts or heterojunction blocking contacts. The devices are fabricated on a two-layer in situ grown MOCVD Hg1-xCdxTe wafer with a capping layer of x=0.31 and an LWIR absorbing layer of x=0.22. The experimental data clearly demonstrates the difficulty of forming n +/n blocking contacts on LWIR material, and indicates that heterojunctions are the only viable technology for forming effective blocking contacts to narrow bandgap semiconductors

Published in:

Electron Devices, IEEE Transactions on  (Volume:44 ,  Issue: 2 )