Recombination at dangling bonds and band tails: Temperature dependence of photoconductivity in hydrogenated amorphous silicon

On thermal quenching of the photoconductivity in hydrogenated amorphous silicon

“…Weak doping leaves the concentration of DB defects essentially the same as in undoped samples and only changes the relative number of charged to neutral DBs (Vanier 1983) by shifting the dark Fermi level EF. through the DB density of states.…”

“…This formalism was originally used to model the steady-state photoconductivity for materials having an arbitrary density of states whose charge states are not energy correlated. The formalism was extended by Vaillant and Jousse (1986), Vaillant et al (1988) and Smail and Mohammed-Brahim (1991) to include DB states, which have a correlation energy when occupied by two electrons.…”

“…We shall discuss Downloaded by [Monash University Library] at 19:01 11 April 2015 these processes in a later section. Keeping in mind that these processes do occur, we use the formalism developed by Simmons and Taylor (197 1) and extended by Vaillant and Jousse (1986), Vaillant et al (1986Vaillant et al ( , 1988 and Smail and Mohammed-Brahim (1991) to model the steady-state op(T). This formalism assumes that conduction and recombination occur only via free carriers.…”

“…Some workers assumed recombination occurs by capture of free carriers only through DB states and neglected the traffic through the tail states for simplicity (Okamoto, Kida and Hamakawa 1984, Morgado 1991, Hubin, Shah and Sauvain 1992, while others ignored the double occupancy of the DBs and treated them in the same manner as tail states (Gu, Han, Li andZhao 1986, McMahon andXi 1986). Vaillant, Jousse and Bruyere (1988) and Smail and Mohammed-Brahim (1991) included all gap states properly. However, despite all these studies, the cause of the TQ of the photoconductivity in a-Si : H has not been clearly unveiled.…”

Recombination traffic in highly crystallized undoped microcrystalline Si films studied by steady state photoconductivity

“…Several numerical and experimental observations of the temperature and intensity dependence of photoconductivity [r ph (T,/)] were used to explain the physics of the gap states over a wide range in bandgap of a-Si:H [10][11][12][13]. Whereas less attention is paid on SSPC on Ac-Si:H films [9,14].…”