Electric Field Effects on Bound to Quasibound Intersubband Absorption and Photocurrent in GaAs/AlGaAs Quantum Wells
Bound to quasi-bound intersubband transitions in multiquantum wells are of particular interest for high responsivity infrared photodetectors. However, contrary to the bound-to-bound case, no systematic comparison between photoconduction (PCS) and absorption (AS) spectra has been performed in that system. We have used Fourier Transform Infrared Spectroscopy to determine simultaneously the influence of an applied electric field on AS and PCS spectra. Two kinds of well are under study: a symmetric square and an asymmetric step quantum well, both with a quasi-bound excited state. Absorption and photocurrent spectra are found to be different in shape. Moreover, the electric field dependence of the spectra is different: photocurrent threshold is red shifted, whereas the absorption peak follows Stark shift effect. This suggests a sequential mechanism involved in the photocurrent collection, governing the response lineshape of the detector.
KeywordsQuantum Well Applied Electric Field Ionization Threshold Stark Shift Electric Field Effect
Unable to display preview. Download preview PDF.
- 2.J. S. Smith, L. C. Chiu, S. Margalit, and A. Yariv, A new infrared detector using electron emission from multiquantum wells, J. Vac. Sci. Technol. B1:376 (1983).Google Scholar
- 4.B. F. Levine, C. G. Bethea, K. K. Choi, J. Walker, and R. J. Malik, Bound-to-extended state absorption GaAs superlattice transport infrared detectors, Appl. Phys. Lett. 64:1591 (1988).Google Scholar
- 6.H. C. Liu, A. G. Steele, M. Buchanan, and Z. R. Wasilewski, Effects of the Upper State Position and the Number of Wells in the Performance of Intersubband Quantum Well Detectors, in: “Intersubband Transitions in Quantum Wells,” E. Rosencher, B. Vinter, and B. Levine, ed., Plenum, London (1992).Google Scholar
- 7.E. Martinet, F. Luc, E. Rosencher, P. Bois, and S. Delaître, Electrical tunability of infrared detectors using compositionally asymetrical GaAs/AlGaAs quantum wells, Appl. Phvs. Lett. (To be published).Google Scholar
- 13.E. Rosencher, E. Martinet, F. Luc, P. Bois, and E. Böckenhoff, Dicrepancies between photocurrent and absorption spectroscopies in intersubband photoionization from GaAs/AlGaAs multiquantum wells, Apol. Phys. Lett. 59: (1991).Google Scholar
- 17.A. G. Petrov and A. Y. Shik, Photoionization of quantum wells in a strong electric field., Sov. Phys. Semicond. 24:896 (1990).Google Scholar
- 19.E. Rosencher and P. Bois, Model system for optical nonlinearities: Asymmetric quantum wells, Phys. Rev.B 44: (1991).Google Scholar
- 23.B. Deveaud, A. Chomette, F. Clérot, and A. Regreny, Subpicosecond Luminescence Study of Capture and Intersubband Relaxation in Quantum Wells, in: “Intersubband Transitions in Quantum Wells,” E. Rosencher, B. Vinter, and B. Levine, ed., Plenum, London (1992).Google Scholar