Experimental and Atomistic Theoretical Study of Degree of Polarization from Multi-layer InAs/GaAs Quantum Dots

Recent experimental measurements, without any theoretical guidance, showed that isotropic polarization response can be achieved by increasing the number of QD layers in a QD stack. Here we analyse the polarization response of multi-layer quantum dot stacks containing up to nine quantum dot layers by linearly polarized PL measurements and by carrying out a systematic set of multi-million atom simulations. The atomistic modeling and simulations allow us to include correct symmetry properties in the calculations of the optical spectra: a factor critical to explain the experimental evidence. The values of the degree of polarization (DOP) calculated from our model follows the trends of the experimental data. We also present detailed physical insight by examining strain profiles, band edges diagrams and wave function plots. Multi-directional PL measurements and calculations of the DOP reveal a unique property of InAs quantum dot stacks that the TE response is anisotropic in the plane of the stacks. Therefore a single value of the DOP is not sufficient to fully characterize the polarization response. We explain this anisotropy of the TE-modes by orientation of hole wave functions along the [-110] direction. Our results provide a new insight that isotropic polarization response measured in the experimental PL spectra is due to two factors: (i) TM[001]-mode contributions increase due to enhanced intermixing of HH and LH bands, and (ii) TE[110]-mode contributions reduce significantly due to hole wave function alignment along the [-110] direction. We also present optical spectra for various geometry configurations of quantum dot stacks to provide a guide to experimentalists for the design of multi-layer QD stacks for optical devices. Our results predict that the QD stacks with identical layers will exhibit lower values of the DOP than the stacks with non-identical layers.Comment: 10 pages, 7 figures, and 1 tabl

Penguatan Karakter Masyarakat melalui Implementasi Critical Thinking Desa Grenden, Kecamatan Puger

Permasalahan sosial yang terjadi pada kalangan muda era modern terlebih di tengah-tengah perkembangan glob-alisasi yang semakin pesat tentunya berdampak besar pada tingkat moralitas dan pembentukan karakter generasi muda bangsa. Hal ini dibuktikan dengan bagaimana permasalahan sosial yang banyak ditemukan di tengah-tengah masyarakat dari desa hingga kota, dari yang terpencil hingga yang serba ada. Penyebabnya pun banyak dikarenakan oleh pola pikir dan pendidikan karakter yang masih minim di masyarakar. Fenomena tersebut ditemukan salah satunya di Kawasan Desa Greden, Kecamatan Puger, Kabupaten Jember. Cara menanggulangi permasalahan yang terjadi yaitu dengan cara pendampingan melalui sosialisasi kepada generasi muda melalui lembaga dan kegiatan masyarakat. Data diperoleh dari observasi dan wawancara kepada pihak-pihak yang berkompeten, sosialisasi melibatkan siswa dari beberapa lembaga dan pemuda desa yang tergabung dalam kelompok masyarakat yang ada

Konsep Dakwah Politik Mohammad Natsir di Indonesia

This research is included in library research with a socio-historical approach. This research is included a qualitative research. This research belongs to the type of historical study through the study of documents or texts. This study discusses the concept of Mohammad Natsir's political da'wah and his methods and strategies aimed at grounding and reintroducing the concept. Sources of data in this research consisted of primary and secondary sources of books/writings. This research data collection through documentation using content analysis techniques. The results of this research indicated that in political da'wah activities, Mohammad Natsir had the concept of modernization in Islamic p olitics. The essence of Natsir's concept of political modernism is to apply the teachings of Islamic spiritual, social and political values ​​contained in the Qur'an and Hadith, but still adapted and be opened to the period of times. Natsir carried out political da'wah with three methods, namely through the government field, the government field and the community development field. Natsir's political da'wah method was carried out using a da'wah strategy with actions, in writing, and orally. The implications of this research are expected to be the development of broader da'wah theories, especially those related to political da'wah in Indonesia