Effect of doping concentration on the conductivity and optical properties of p-type ZnO thin films

p-Channel and n-Channel Thin-Film-Transistor Operation on Sprayed ZnO Nanoparticle Layers

“…The mobility of type A NP layers (hole) was larger than the mobility of type B ones (electron), whereas the hole mobility is smaller than the electron mobility in usual single crystal ZnO [19]. Recent nitrogen-doped ZnO-NP layers containing grain boundaries (GBs) show similar behaviors [13][14][15]. Generally, the GBs affect the carrier transfer, since the majority carriers will be trapped at the defects in GBs' site with forming energy barriers as shown in Figure 3(a).…”

“…One difficulty faced by ZnO application is that it is challenging to obtain p-type conductivity with this material because of the compensation by intrinsic donor defects such as oxygen vacancies and Zn interstitials [7,8]. Various approaches have been reported for achieving p-type ZnO layers, like doping with group Ia [9,10], Ib [11], and V [12][13][14][15] elements, codoping with group Ia, III, or V elements [16,17], and so on [18,19]. However, few results can achieve LED or TFT operations using the obtained p-type layers.…”

Engineering Valence Band Dispersion for High Mobility p-Type Semiconductors

“…Initial attempts at designing p-type TCOs focused on acceptor doping of the high performance n-type TCOs (e.g., In 2 O 3 , ZnO, SnO 2 ) − and is in fact still currently attempted. , The thinking behind this procedure is that the fabrication of a p–n homojunction would be relatively facile if p-type SnO 2 was to be combined with n-type SnO 2 , for example. Recent theoretical studies have pointed out that due to the large electron affinities and ionization potentials of these systems − there is a thermodynamic driving force for n-type defects (excess electrons) increasing the probability that even if holes could form they would result in immediate compensation by intrinsic donor defects under all growth conditions. ,, In addition to this, the localized O 2p states at the top of the valence band promote a tendency to form polaronic defects localized on oxygen sites .…”