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Papers by Rangga Ramdani
Physical Review B, 2010
The tunnel photocurrent between a gold surface and a free-standing semiconducting thin film excit... more The tunnel photocurrent between a gold surface and a free-standing semiconducting thin film excited from the rear by above bandgap light has been measured as a function of applied bias, tunnel distance and excitation light power. The results are compared with the predictions of a model which includes the bias dependence of the tunnel barrier height and the bias-induced decrease of surface recombination velocity. It is found that i) the tunnel photocurrent from the conduction band dominates that from surface states. ii) At large tunnel distance the exponential bias dependence of the current is explained by that of the tunnel barrier height, while at small distance the change of surface recombination velocity is dominant. 21/05/2010 * * A is the effective Richardson constant, T is the temperature and k is the Boltzmann constant. The calculation of the tunnel current can be simplified if p te J J <<. This assumption is valid provided the tunnel gap is not too small and will be justified below by comparison with the experimental results. In the opposite extreme case, the tunnel photocurrent is equal to the injected photocurrent (J p) and the photovoltage is small. Similarly, it will be assumed that th J << s J .
Physical Review B, 2010
The tunnel photocurrent between a gold surface and a free-standing semiconducting thin film excit... more The tunnel photocurrent between a gold surface and a free-standing semiconducting thin film excited from the rear by above bandgap light has been measured as a function of applied bias, tunnel distance and excitation light power. The results are compared with the predictions of a model which includes the bias dependence of the tunnel barrier height and the bias-induced decrease of surface recombination velocity. It is found that i) the tunnel photocurrent from the conduction band dominates that from surface states. ii) At large tunnel distance the exponential bias dependence of the current is explained by that of the tunnel barrier height, while at small distance the change of surface recombination velocity is dominant. 21/05/2010 * * A is the effective Richardson constant, T is the temperature and k is the Boltzmann constant. The calculation of the tunnel current can be simplified if p te J J <<. This assumption is valid provided the tunnel gap is not too small and will be justified below by comparison with the experimental results. In the opposite extreme case, the tunnel photocurrent is equal to the injected photocurrent (J p) and the photovoltage is small. Similarly, it will be assumed that th J << s J .