Abstract-III-nitride terahertz photodetectors for the Reststrahlen gap of intersubband optoelectronics

R. Paiella,  H. Durmaz,  F. F. Sudradjat; D. Nothern, G. C. Brummer, W. Zhang; J. Woodward,  T. D. Moustakas

https://www.spiedigitallibrary.org/proceedings/Download?fullDOI=10.1117/12.2274040

We report the development of terahertz intersubband photodetectors based on GaN/AlGaN quantum wells, covering the frequency range that is fundamentally inaccessible to existing III-V semiconductor devices due to Reststrahlen absorption. Two different approaches have been employed to mitigate the deleterious effects of the intrinsic polarization fields of nitride heterostructures: the use of suitably designed double-step quantum wells, and epitaxial growth on semipolar GaN substrates. Promising results are obtained with both approaches, which could be extended to other device applications as a way to utilize the intrinsic advantages of nitride semiconductors for THz intersubband optoelectronics.
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Abstract-Terahertz intersubband photodetectors based on semi-polar GaN/AlGaN heterostructures

Habibe Durmaz1, Denis Nothern1, Gordie Brummer1, Theodore D. Moustakas1 and Roberto Paiella1

http://scitation.aip.org/content/aip/journal/apl/108/20/10.1063/1.4950852

Appl. Phys. Lett. 108, 201102 (2016); http://dx.doi.org/10.1063/1.4950852

Terahertz intersubband photodetectors are developed based on GaN/AlGaN quantum wellsgrown on a free-standing semi-polar (202¯1¯)$(20\overline{2}\overline{1})$GaN substrate. These quantum wells are nearly free of the polarization-induced internal electric fields that severely complicate the design of nitride intersubband devices on traditional c-plane substrates. As a result, a promising bound-to-quasi-bound THz photodetector design can be implemented. Pronounced photocurrent peaks at the design frequency near 10 THz are measured, covering frequencies that are fundamentally inaccessible to existing arsenide intersubband devices due to reststrahlen absorption. This materials system provides a favorable platform to utilize the intrinsic advantages of nitride semiconductors for THz optoelectronics.