Origin of ‘‘residual’’ persistent photoconductivity in selectively doped GaAs/AlxGa1-xAs heterojunctions

Theis, T. N.; Wright, S. L.
May 1986
Applied Physics Letters;5/19/1986, Vol. 48 Issue 20, p1374
Academic Journal
We present experimental results which clearly separate the various physical mechanisms which cause persistent photoconductivity in GaAs/AlxGa1-xAs heterojunctions. For high Al mole fraction the major contribution is from the donor-related DX center. This contribution is eliminated by reducing the Al mole fraction x, but we observe a ‘‘residual’’ effect for x<=0.2. We show that this is due to the persistent photovoltage developed between channel and semi-insulating substrate. Charge trapping in the epitaxial GaAs buffer layer contributes negligibly, contrary to the assumptions of other workers. This is demonstrated by fabricating modulation-doped field-effect transistors of low Al mole fraction on conductive substrates. In these devices persistent photoconductivity is eliminated as long as the substrate (back gate) potential is fixed with respect to the channel.


Related Articles

  • 1,8-octanedithiol as a processing additive for bulk heterojunction materials: Enhanced photoconductive response. Coates, Nelson E.; Hwang, In-Wook; Peet, Jeffrey; Bazan, Guillermo C.; Moses, Daniel; Heeger, Alan J. // Applied Physics Letters;8/18/2008, Vol. 93 Issue 7, p072105 

    We present measurements of steady state and transient (τ<70 ps) photoconductivity of the low bandgap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] mixed with [6,6]-phenyl C71-butyric acid methyl ester films processed...

  • Preface to Special Topic: Selected Papers from the Photovoltaic Technical Conference, Aix en Provence, France, 2014. Bermudez, Veronica // Journal of Renewable & Sustainable Energy;2015, Vol. 7 Issue 1, p1 

    An introduction is presented in which the editor discusses various reports within the issue on topics including a cell concept based on silicon heterojunctions, a solution for high efficiency modules, and the use of microwave photoconductivity in metal thin films.

  • Negative photoconductivity of two-dimensional holes in GaAs/AlGaAs heterojunctions. Chou, M. J.; Tsui, D. C.; Weimann, G. // Applied Physics Letters;9/15/1985, Vol. 47 Issue 6, p609 

    A negative photoconductivity is observed due to the two-dimensional (2D) holes at GaAs/Al0.5Ga0.5As heterojunctions under illumination by a red light-emitting diode below ∼6 K. The photoconductivity follows a nonexponential decay after the illumination is turned off. Quantum transport...

  • Ultraviolet bandpass Al0.17Ga0.83N/GaN heterojunction phototransitors with high optical gain and high rejection ratio. Lee, M. L.; Sheu, J. K.; Shu, Yung-Ru // Applied Physics Letters;2/4/2008, Vol. 92 Issue 5, p053506 

    Ultraviolet Al0.17Ga0.83N/GaN-based heterojunction phototransistors (HPTs) grown by metal-organic vapor-phase epitaxy were demonstrated. The HPTs showed a bandpass spectral responsivity ranging from 280 to 390 nm. With a bias voltage of 6 V, the responsivity at an incident of 340 nm was as high...

  • Imaging of nanoscale charge transport in bulk heterojunction solar cells. Hamadani, Behrang H.; Gergel-Hackett, Nadine; Haney, Paul M.; Zhitenev, Nikolai B. // Journal of Applied Physics;Jun2011, Vol. 109 Issue 12, p124501 

    We have studied the local charge transport properties of organic bulk heterojunction solar cells based on the blends of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester with a photoconductive atomic force microscope (PCAFM). We explore the role of morphology on transport of...

  • The Role of the AIGaAs Doping Level on the Optical Gain of Two-Dimensional Electron Gas Photodetectors. Nabet, Bahram; Romero, Murilo A.; Cola, Adriano; Quaranta, Fabio // Journal of Electronic Materials;Feb2004, Vol. 33 Issue 2, p123 

    We compare the optical response of two modulation-doped heterojunction photodetectors with identical growth structure, differing only in the doping level of the wide band material. The larger photoresponse of the higher doped device cannot be explained as photoconductive gain because neither the...

  • Conducting properties of planar irradiated and pristine silicon-fullerite-metal structures. Berdinsky, A. S.; Fink, D.; Yoo, J. B.; Chun, H. G.; Chadderton, L. T.; Petrov, A. V. // Applied Physics A: Materials Science & Processing;May2005, Vol. 80 Issue 8, p1711 

    Au/C60/p-Si sandwich structures can be easily obtained by evaporation of a thin fullerite (C60) film on a silicon substrate and a thin Au film on top of the C60 film. In this case a C60/p-Si p-n heterojunction appears. Both the dark and photoconductivities of the planar pristine and irradiated...

  • HgCdTe heterojunction contact photoconductor. Smith, D. L.; Arch, D. K.; Wood, R. A.; Scott, M. Walter // Applied Physics Letters;1984, Vol. 45 Issue 1, p83 

    A new photoconductor device structure is described utilizing a heterojunction contact which incorporates a higher band-gap HgCdTe alloy between the metal contact and the normal band-gap photoconductor. A theoretical treatment of the heterojunction contact photoconductor (HCP) device shows that...

  • Modeling the effect of the structure of polymer photocells on their absorption spectrum. Shikler, Rafi; Friend, Richard H. // Journal of Applied Physics;7/1/2007, Vol. 102 Issue 1, p013105 

    We present a framework for the calculation of light absorption in multicomponent polymer photocells. We have modeled a periodic lateral structure of two polyfluorene conjugated polymers with complementary absorption spectra. We show how the coupling induced by scattering at the interfaces...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics