APPENDIX A. LIST OF SYMBOLS 513
J current density
JL photocurrent density
Jph photon particle current density
mean free path between successive collisions
Ln diffusion length for electron
Lp diffusion length for holes
mo free electron mass
m∗e electron mass
m∗h hole mass
m∗dos density of states mass
m∗σ conductivity mass
m∗hh mass of the heavy hole
m∗h mass of the light hole
m∗r reduced mass of the electron-hole system
M, Me,Mhmultiplication factor, multiplication factor for electrons,
mulitplication factor for holes
n electron concentration in the conduction band
ni intrinsic electron concentration in the conduction band
nd electrons bound to the donors
np(np) equilibrium electron density in thep-side (n-side) of ap-njunction
Ncv joint density of states for electrons and holes
Ne(E) density of states of electrons in the conduction band
Nh(E) density of states of holes in the valence band
Nc(E) effective density of states in the conduction band
Nv(E) effective density of states in the valence band
Nd donor density
Na acceptor density
N 2 D(E) 2-dimensional density of states
Nt density of impurity states (trap states)
Nab acceptor concentration in the base of annpnBJT
Nde donor concentration in the emitter of annpnBJT
Ndc donor concentration in the collector ofnpnBJT