Oxygen on III-V Semiconductors

Lastly, we come to the adatom charge transfer, which is obtained from 

Having formulated the ANG model, in terms of a 1-band metallic substrate, we now apply it to a 2-band semiconductor. 

For atomic oxygen, I = — 13.6eV (Day and Selbin 1962), while A = —1.48eV is below the vacuum level of the isolated oxygen atom. Since image-charge 

5This amounts to introducing a contribution of — 7r 1 / nds into (4.100), which re- 

---

A useftil applicadon of time-dependent PL is the assessment of the quality of thin III-V semiconductor alloy layers and interfaces, such as those used in the fabri-cadon of diode lasers. For example, at room temperature, a diode laser made with high-quality materials may show a slow decay of the acdve region PL over several ns, whereas in low-quality materials nonradiative centers (e.g., oxygen) at die cladding interface can rapidly deplete the free-carder population, resulting in much shorter decay times. Measurements of lifetime are significandy less dependent on external condidons than is the PL intensity. 

Having established the expressions for the chemisorption functions of an AB-type chain, we can now employ them in calculating AE (4.101) and Aq (4.102) for oxygen on narrow-gap III-V semiconductors. Specifically, we are interested in GaSb, InAs and InSb. The choice of narrow-gap substrates ensures that the approximation made regarding the contour C in (4.92) remains valid. Results are presented for the 47-case only. 

---