Electron hole effective mass

The other semiconductor, apart from CdSe, that has been studied with deliberate emphasis on quantum size effects, is PbSe (see Table 10.3). There are several reasons for this. One is the long-known use of CD to deposit PbS and later PbSe. Second, and of particular importance, the electron/hole effective mass in PbSe is very... 

Bandgap (eV) Mobility (cm V s ) Electrons Holes Effective mass (m /mg) Electrons Holes ... 

H symmetry point e(h) electron (hole) effective mass... 

Where b is Planck s constant and m and are the effective masses of the electron and hole which may be larger or smaller than the rest mass of the electron. The effective mass reflects the strength of the interaction between the electron or hole and the periodic lattice and potentials within the crystal stmcture. In an ideal covalent semiconductor, electrons in the conduction band and holes in the valence band may be considered as quasi-free particles. The carriers have high drift mobilities in the range of 10 to 10 cm /(V-s) at room temperature. As shown in Table 4, this is the case for both metallic oxides and covalent semiconductors at room temperature. 

Near k = 0 the electron and hole effective masses must be isotropic and constant. For a nanoparticle, the uncertainty in the exciton position depends upon its size. Ax 2R. If the relation between energy and momentum is independent of particle size the exciton... 

Enright B, Fitzmaurice D (1996) Spectroscopic determination of electron and hole effective masses in a nanociystalline semiconductor film J Phys Chem 100 1027-1035... 

Here k is the Fermi wave vector determined from the value of the hole concentration p assuming a spherical Fermi surface, m is the hole effective mass taken as 0.5/no (mo is the free electron mass), is the exchange integral between the holes and the Mn spins, and h is Planck s constant. The transverse and longitudinal magnetic susceptibilities are determined from the magnetotransport data according to x = 3M/dB and xh = M/B. 

TABLE 3 Electron and hole effective masses in InN in units of mo. 

A6.4 Luttinger and Bir-Pikus parameters of GaN and AIN A6.5 Electron and hole effective masses of GaN and AIN A6.6 Deformation potentials of GaN and AIN A6.7 Momentum matrix elements of GaN A6.8 Subband structures of GaN/AlGaN quantum wells A6.9 Optical gain of bulk GaN and GaN/AlGaN quantum wells... 

Of course, the details of the gain spectra depend on the dimensionality of the active material (bulk, quantum well, etc.) and on the details of the band structure. For such detailed calculations we refer to Chapter A6 of this volume. However, it is important to note that due to the specific band structure of the nitrides, the carrier densities needed to achieve inversion and optical gain are very large compared to other m-V semiconductors. In particular, both the electron effective mass (nw = 0.22 [7]) as well as the hole effective mass (mi, 2.0 [8-10]) are three- to four-fold larger than in GaAs. For the same reason, however, the maximum gain obtainable from nitride structures is also larger. 

The energy bands are no longer described by the -k dispersion relations, but instead by a density-of-states distribution N E), illustrated in Fig. 1.6. Also the electron and hole effective masses must be redefined as they are usually expressed as the ciu-vature of (k). 

Eq. 1. h Planck s constant e dielectric constant m, electron mass m hole effective mass this is indeed the case for isolated silicon particles [11] as well as for compact films of nc-Si (25]... 

Figure 7. Schematic view of polysilane band structure. The abbreviations and symbols are defined as follows me, effective mass of electrons mh effective mass of holes lumi., luminescence abs., absorption T, k = 0 point and k,...

---