1. Vancouver 081 Free carrier induced substrate heating of the epitaxially grown GaMnAs Institute of Physics AS CR, Prague Vit Novak, Kamil Olejnik, Miroslav Cukr

2. Vancouver 082 GaMnAs Problem: limited Mn solubility growth at T=220°C growth at T=230°C 7%Mn, 50 nm

3. Vancouver 083 Measuring the (low) temperature thermocouple xpoor coupling optical pyrometry xweak radiation xsubstrate transparent Band-gap spectroscopy Shanabrook et al. (1992), Johnson et al. (1993), Thompson et al. (1997) commercially by kSA (BandiT)

4. Vancouver 084 Band-gap spectroscopy spectrometer substrate heater GaAs 160°C sufficient! > ~

5. Vancouver 085 Growth minimum change in T s measured by Tc constant heater power

6. Vancouver 086 Growth minimum change in T s measured by Tc large change in T s measured by BES ! constant heater power

7. Vancouver 087 Absorption spectrum substrate + GaMnAs band-gap region

8. Vancouver 088 Absorption spectrum really change of T s ! substrate + 40°C + GaMnAs band-gap region

9. Vancouver 089 Absorption spectrum really change of T s ! substrate + 40°C + GaMnAs band-gap region NIR phonons free carriers substrate + GaMnAs

10. Vancouver 0810 Model I. naively: solution: But ! obscured parameters inconsistencies with experiment

11. Vancouver 0811 Radiation heat exchange 1 2 Q in-2 Q out-2 Q out-1

12. Vancouver 0812 Radiation heat exchange 1 2 Q in-2 Q out-2 Q out-1

13. Vancouver 0813 Radiation heat exchange phonons interband substrate/epilayer absorptance  s ( ) absorptance

14. Vancouver 0814 Radiation heat exchange phonons interband free holes absorptance substrate/epilayer absorptance  s ( )

15. Vancouver 0815 Radiation heat exchange phonons interband free holes absorptance substrate/epilayer absorptance  s ( )

16. Vancouver 0816 Radiation heat exchange phonons interband free holes absorptance substrate/epilayer absorptance  s ( )

17. Vancouver 0817 Radiation heat exchange phonons interband radiation sources free holes ~250°C absorptance, radiance

18. Vancouver 0818 Radiation heat exchange phonons interband ~900°C radiation sources free holes absorptance absorptance, radiance ~250°C

19. Vancouver 0819 Radiation heat exchange phonons interband radiation sources free holes background absorptance, radiance ~250°C ~900°C

20. Vancouver 0820 Radiation heat exchange phonons interband substrate radiation free holes background substrate absorptance, radiance ~250°C ~900°C

21. Vancouver 0821 Model II. better: heater ( 200°C ) cells ( ~ 900°C ) background ( > 77K, < 200°C ) i :i : > ~  s (, t ) : t ff

22. Vancouver 0822 Results before growth: long after growth:

23. Vancouver 0823 Results before growth: long after growth: time evolution: T h = 320°C T c = 950°C T b = 40°C

24. Vancouver 0824 Implications for  T reduction T BES -locked substrate heater power (problem: heat capacity of heater)

25. Vancouver 0825 Implications for  T reduction T BES -locked substrate heater power (problem: heat capacity of heater) sample holder (or sample!) with initially strong IR absorption

26. Vancouver 0826 Implications for  T reduction T BES -locked substrate heater power (problem: heat capacity of heater) sample holder (or sample!) with initially strong IR absorption

27. Vancouver 0827 Implications for  T reduction T BES -locked substrate heater power (problem: heat capacity of heater) sample holder (or sample!) with initially strong IR absorption

28. Vancouver 0828 Implications for  T reduction T BES -locked substrate heater power (problem: heat capacity of heater) on Mo-block w/ sublayer sample holder (or sample!) with initially strong IR absorption

29. Vancouver 0829 Bonus: record Curie temperature 185K also: Nottingham group Thank you !