Effects of incident-light-intensity-dependent band gap narrowing on barrier heights of p-doped AlxGa1xAsGaAs heterojunction devices》.pdfVIP

Infrared Physics Technology 63 (2014) 193–197 Contents lists available at ScienceDirect Infrared Physics Technology journal homepage: www.else /locate/infrared Effects of incident-light-intensity-dependent band gap narrowing on barrier heights of p-doped AlxGa1xAs/GaAs heterojunction devices P.K.D.D.P. Pitigala, Y.F. Lao, A.G.U. Perera ⇑ Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA h i g h l i g h t s Light-intensity causes zero VB offsets in low-barrier IR detectors at T 50 K. PL shows band gap increase in undoped GaAs with illumination at T = 25 K. Undoped GaAs and p-AlGaAs are reluctant to BGN caused by incident light intensity. Undoped GaAs/p-doped Al0.01Ga0.99As combination suitable for FIR/THz detectors. a r t i c l e i n f o a b s t r a c t Article history: Band gaps of semiconductor materials are reduced due to band gap narrowing (BGN). Photoluminescence Received 3 October 2013 measurements on GaAs and AlGaAs thin films revealed a dependency of incident light intensity, and tem- Available online 18 January 2014 perature in BGN in addition to the doping density. As a result, the valence band offset of p-doped GaAs/ AlGaAs heterojunctions were reduced under illumination and high temperatures. We present evidence of Keywords: incident-light-intensity causing barrier reduction at temperature 50 K causing zero valence band offsets Incident-light-intensity in low-barrier heterostructures such as p-GaAs/Al0.01Ga0.99As, in ad