Progress in ZnO Acceptor Doping: What Is the Best Strategy?

Table 1

Summary of room temperature Hall data for p-type ZnO.

Growth technique	Structure^a	Acceptor doping scheme	Hole concentration (10^18 cm^−3)	Mobility (cm^2 V^−1 s^−1)	Resistivity (Ω-cm)	Reference
CVD	U	NH3 and excess Zn	0.015	12	34	Minegishi et al. [19]
MBE	SC	RF plasma N2	0.09	2	40	Look et al. [20]
RF diode sputtering	SC	Ga, N codoping	0.09	6	11.77	Singh et al. [21]
MBE (ECR O source)	U	Sb-doped + 800°C anneal	1.7	20	0.2	Xiu et al. [22]
DC reactive magnetron sputtering	PC^b	Li-doped	0.14	2.65	16.4	Zeng et al. [23]
RF magnetron sputtering	SC	Ga and N codoping (N2 sputtering gas)	0.39	0.4	38	Kumar et al. [24]
Plasma assisted MOVPE	U	NO plasma as O and N source	2.29	1.59	1.72	Zeng et al. [25]
Sol-gel	PC	Al and N codoping + O anneal	0.08–0.2	1.6–1.73	19–45	Dutta et al. [26]
RF magnetron sputtering	SC	O and As dual implantation	6.8–19.8	19–32.9	0.05–0.55	Kim et al. [27]
MOVPE	U	P-doped	0.21	1.2	—	Du et al. [28]
PLD	PC	Na-doped + 254 nm illumination	0.21	7.9	3.8	Lin [29]
PLD	SC	N^+ implantation + dynamic annealing	0.024–0.52	0.7–3.71	18–71	Myers et al. [30]
Plasma assisted MBE	U	Sb-doped + 800^oC anneal	0.06	—	—	Huang et al. [31]
MOVPE	SC	As-doped via outdiffusion	0.35	0.79	—	Shi et al. [32]
Magnetron sputtering	U	P and N codoping + 800°C anneal	1.16	1.35	3.98	Sui et al. [33]
Plasma assisted MBE	SC	Na doping	0.002	0.4	8575	Ding et al. [34]
Spin coating	PC	N, Al codoping + double anneal in NH3 and N2	0.61	198.8	0.05	Kalyanaranan et al. [35]
MOVPE	SC	3% NO in N2	3.6	0.4	4.4	Reynolds et al. [36]

aU: undefined; SC: single crystal; PC: polycrystalline. All are thin films.
^b(002) preferential orientation.