Acceptor complexes in germanium

The UV-vis spectral analysis confirms the appearance of a new charge-transfer absorption band of the complexes of colorless a-donors (R3MH) and the n-acceptor (TCNE). In accord with Mulliken theory, the absorption maxima (Act) of the [R3MH, TCNE] complexes shift toward blue with increasing ionization potential of the metal hydrides (i.e., tin > germanium > silicon) as listed in Table 8. 

Other H-related complexes with Be and Zn double acceptors and with Cu have also been identified and they are discussed in Sect. 7.3.1.1 where the neutral multi-charged acceptors in germanium are presented. 

In a germanium sample from an As-doped crystal pulled in vacuo and contaminated with Cu, the PTIS spectrum of a CuX centre has been reported by Sirmain et al. [156]. Its first ionization energy is 10.05 meV and the ther-malized energy is 9.15 meV. Piezospectroscopic measurements indicate a C v symmetry and the dissociation conditions of this complex have led to the tentative attribution of CuX to a (Cus, As) acceptor complex, which should normally behave as a double acceptor. 

Bimetallic donor-acceptor complexes can be formed with tin and germanium porphyrins as shown in Equation The reaction of... 

Germanium was the first crystalline semiconductor in which a number of shallow acceptor and donor complexes were discovered that were unambiguously proven to contain hydrogen. This series of discoveries began in the 1970s when several laboratories conducted research and development efforts with the aim of producing ultra-pure Ge single crystal for radiation... 

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