Materials for Future Quantum Dot-Based Memories

Table 1

Electronic properties and storage times at 300 K for various QD material systems. The bold entries are theoretical predictions based on 8-band-k·p calculations or estimations from the band offsets.

Material	Type	E loc (meV)	𝜎∞ (cm^2)	Storage time at (300 K)	Reference
Ge/Si	Hole	350*	1·10^−13	0.1 µs	[16]
InAs/GaAs	Electron	95	1·10^−11	0.4 ps	[17]
InAs/GaAs	Electron	160*	10^−11 to 10^−10	0.1 ps	[18, 19]
InAs/GaAs	Electron	290	2·10^−14	200 ns	[20]
InAs/GaAs	Hole	210	7·10^−14	1 ns	[20]
InAs/Al0.6Ga0.4As	Hole	560	7·10^−15	5 ms	[21]
InAs/Al0.9Ga0.1As	Hole	710	4·10^−15	1.6 s	[22]
GaSb/GaAs	Hole	337	1·10^−13	10 ns	[23]
GaSb/GaAs	Hole	450	1·10^−12	1 µs	[15]
GaSb/GaAs	Hole	460	7·10^−12	100 ns	[12]
GaSb/GaAs	Hole	760	5·10^−11	2 ms	[12]
GaSb/Al0.1Ga0.9As	Hole	670	1·10^−12	2 ms	[24]
GaSb/Al0.3Ga0.7As	Hole	800	5·10^−12	80 ms	[12]
InP/Ga0.5In0.5P	Electron	220	1·10^−8	0.04 ps	[25]
In0.25Ga0.75As/GaAs/GaP	Hole	489*	2·10^−13	3 µs	[26]
GaSb/ 𝐀𝐥𝟎.𝟗𝐆𝐚𝟎.𝟏 As	Hole	~1250	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	50 h to 100 yr	[12]
GaSb/GaP	Hole	~1400	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	1 yr to 100 k yr	[27]
GaSb/AlP	Hole	~1900	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	1 G yr to 100 T yr	[27, 28]
GaSb/AlSb **	Electron	~1200	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	36 h to 40 yr	[28]
GaN/AlN	Electron	~2000	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	10 G yr to 10 P yr	[29]
InAs/AlSb **	Electron	~2150	𝟏𝟎^−𝟏𝟓 – 𝟏𝟎^−𝟏𝟎	100 T yr to 1 E yr	[28]

The values marked with an asterisk (*) are not localization energies but ensemble activation energies. (**) These heterostructures do not facilitate QDs, but they form unstrained ordinary quantum wells.