Far-infrared optically detected cyclotron resonance in GaAs layers and low-dimensional structures

Abstract

Novel far-infrared optically detected cyclotron resonance (FIR-ODCR) techniques are used to investigate GaAs epilayers and t h e resuits are compared with conventional cyclotron resonance performed at far-infrared frequencies and ODCR at microwave frequencies. The FIROOCR technique shows remarkable resolution and sensitivity and has been applied to investigations of t h e electronic structure of low-dimensional systems. In particular. cyclotron resonance has been optically detected in a GaAsIGaAIAs multiple quantum well ( M a w ) sample and compared with ODCR results performed at microwave frequency. Multi-single quantum wells (MSOW) in an MBE GaAsIGaAIAs structure with different well thicknesses have also been investigated, and by detecting cyclotron resonance via the.FlR-induced changes in the luminescence of the separate wells, the power of the technique to investigate the cyclotron resonance mass versus well thickness in a single sample has been demonstrated. Finally. t h e experimentally determined values of effective mass for different well widths are compared with the theoretical results, showing good agreement.

Terahertz Dynamics of Excitons in GaAs/AlGaAs Quantum Wells

“…This PL quenching is consistent with the interpretation that the FIR radiation heats photoinjected electrons and holes, which in turn heat and decrease peak emission from luminescing excitons [6]. Numerous experiments have optically detected cyclotron resonance [7][8][9][10][11][12][13], and impurity transitions [14,15] in various bulk semiconductors and quantum heterostructures. The equivalence of ODR and conventional transmission techniques in determining the frequency of absorption resonances has been shown clearly (for example, see [10,11]).…”

“…Numerous experiments have optically detected cyclotron resonance [7][8][9][10][11][12][13], and impurity transitions [14,15] in various bulk semiconductors and quantum heterostructures. The equivalence of ODR and conventional transmission techniques in determining the frequency of absorption resonances has been shown clearly (for example, see [10,11]). …”

Energy-Band Structure: Electron and Hole Effective Masses

“…The electron effective mass m/ in GaAs has been determined experimentally by several authors. 2 " 9 We summarize in Table 9 . As we will see in Section 9.1.3 ( Fig.…”

“…Ahmed et al 9 examined the well-thickness dependence of the cyclotron-resonance masses in AlGaAs/GaAs quantum wells. The experimentally-determined mass values for different well widths were compared with the theoretical results of Ekenberg, 59 ' 61 showing good agreement.…”

Electron cyclotron mass in undopedCdTe∕CdMnTequantum wells

“…It was proved to be extremely sensitive and has been successfully used to measure the effective masses of electrons and holes in bulk GaAs, InP, CdTe [5,6,7], and SiC [8]. It was also developed to study 2D electron states in GaAs/(Al,Ga)As heterostructures [9,10,11] and internal transitions of neutral and charged magnetoexcitons [12,13,14]. Another advantage of the ODR technique is related to its spectral selectivity, which allows for selecting the signal from different quantum wells grown in the same structure by analyzing the corresponding photoluminescence emission lines.…”