GaAs/AlGaAs p-type multiple-quantum wells for infrared detection at normal incidence: model and experiment

• Autorzy: Szmulowicz F. , Brown G. J. , Liu H. C. , Shen A. , Wasilewski Z. R. , Buchanan M.
• Konferencja: The Second International Conference on Solid State Crystals '2000 (ICSS'2000) ; (9.10-13.10.2000 ; Zakopane , Poland)
• Języki publikacji: EN

Abstrakty

EN

The development of devices for mid-, long-, and very long-wavelength infrared (IR) detection has benefited greatly from advances in band-gap engineering. Recently, there has been great progress in the development of n-type GaAs/AlGaAs quantum well infrared photoconductor (QWIP) detector arrays in all three technologically important wavelength windows. p-type GaAs/AlGaAs QWIPs represent a viable alternative to n-type GaAs/AlGaAs QWIPs, offering the advantage of normal incidence absorption without the need for grating couplers. The maturity of the MBE of GaAs/AlGaAs layered materials offers the possibility of mass producing low cost, high performance, large size, high uniformity, multicolour, high frequency bandwidth, two-dimensional imagine QWIP arrays. This paper describes progress in optimising the performance of p-type GaAs/AlGaAs QWIP through modelling, growth, and characterisation. Using the 8x8 envelope-function approximation (EFA), a number of structures were designed and their optical absorption calculated for comparision with experiment. Samples were grown by MBE based on the theoretical designs and their photoresponse measured. p-type QWIPs were optimised with respect to the well and barrier widths, alloy concentration, and dopant concentration; resonant cavity devices were also fabricated and temperature dependent photoresponse was measured. The quantum efficiences and the background-limited (BLIP) detectivities under BLIP conditions of our p-QWIPs are comparable to those of n-QWIP; however, the responsivities are smaller. For our mid-IR p-QWIPs, the 2D doping densities of (1-2)x10¹² cm⁻² maximised the BLIP temperature and dark current limited detectivity by operating at around 100 K. At 80 K, the detectivity of the optimum doped sample was 3.5x10¹¹ cmHz¹/²/ W at 10 V bias. Barrier widths greater than 200 A were sufficient to impede the tunneling dark current; resonant cavities enhanced absorption fivefold.

Słowa kluczowe

EN

infrared detector; band-gap engineering; GaAs/AlGaAs; p-type

• Wydawca: Stowarzyszenie Elektryków Polskich ; Polska Akademia Nauk ; Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
• Czasopismo: Opto-Electronics Review
• Rocznik: 2001
• Tom: Vol. 9, No. 2
• Strony: 164--172
• Opis fizyczny: Bibliogr. 22 poz.

Twórcy

autor

Szmulowicz F.

autor

Brown G. J.

autor

Liu H. C.

autor

Shen A.

autor

Wasilewski Z. R.

autor

Buchanan M.

• Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, OH 45433-7707, USA,